{"id":20415,"date":"2021-12-17T13:29:55","date_gmt":"2021-12-17T06:29:55","guid":{"rendered":"https:\/\/www.vietlearn.org\/post\/?p=20415"},"modified":"2021-12-17T13:29:57","modified_gmt":"2021-12-17T06:29:57","slug":"ung-dung-tich-vo-huong-cua-hai-vecto-de-giai-mot-so-dang-toan","status":"publish","type":"post","link":"https:\/\/www.vietlearn.org\/kien-thuc\/ung-dung-tich-vo-huong-cua-hai-vecto-de-giai-mot-so-dang-toan\/","title":{"rendered":"\u1ee8NG D\u1ee4NG T\u00cdCH V\u00d4 H\u01af\u1edaNG C\u1ee6A HAI VECT\u01a0 \u0110\u1ec2 GI\u1ea2I M\u1ed8T S\u1ed0 D\u1ea0NG TO\u00c1N"},"content":{"rendered":"\n<p><\/p>\n\n\n<p>T\u00edch v\u00f4 h\u01b0\u1edbng c\u1ee7a hai vect\u01a1 m\u1ed9t ph\u1ea7n nh\u1ecf trong ch\u01b0\u01a1ng tr\u00ecnh H\u00ecnh h\u1ecdc 10. Tuy v\u1eady t\u00edch v\u00f4 h\u01b0\u1edbng c\u1ee7a hai vec t\u01a1 \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng trong H\u00ecnh h\u1ecdc n\u00f3i ri\u00eang v\u00e0 trong to\u00e1n h\u1ecdc n\u00f3i chung.<\/p>\n<p>Trong c\u00e1c k\u00ec thi ta th\u01b0\u1eddng th\u1ea5y xu\u1ea5t hi\u1ec7n m\u1ed9t s\u1ed1 b\u00e0i to\u00e1n gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh, b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh, h\u1ec7 ph\u01b0\u01a1ng tr\u00ecnh, hay ch\u00fang minh m\u1ed9t s\u1ed1 b\u1ea5t \u0111\u1eb3ng th\u1ee9c ho\u0103c c\u00e1c b\u00e0i to\u00e1n v\u1ec1 c\u1ef1c tr\u1ecb. Nh\u1eefng b\u00e0i to\u00e1n to\u00e1n \u0111\u00f3 n\u1ebfu ta g\u1eb7p d\u1ea1ng c\u1ee7a ch\u00fang v\u00e0 bi\u1ebft \u0111\u01b0\u1ee3c c\u00e1c ph\u01b0\u01a1ng ph\u00e1p gi\u1ea3i c\u1ee7a t\u1eebng d\u1ea1ng th\u00ec \u0111\u00f3 l\u00e0 \u0111i\u1ec1u kh\u00e1 \u0111\u01a1n gi\u1ea3n. Tuy v\u1eady c\u00f3 nh\u1eefng b\u00e0i to\u00e1n c\u00f3 \u0111\u1ed9 kh\u00f3 nh\u1ea5t \u0111\u1ecbnh \u0111\u1ed1i v\u1edbi <a href=\"https:\/\/www.vietlearn.org\" data-internallinksmanager029f6b8e52c=\"2\" title=\"Vietlearn\" rel=\"nofollow\">h\u1ecdc sinh<\/a> b\u1edfi v\u00ec s\u1ef1 \u0111a d\u1ea1ng c\u1ee7a n\u00f3 v\u00e0 \u0111\u1ec3 gi\u1ea3i \u0111\u01b0\u1ee3c th\u00ec ch\u00fang ta c\u1ea7n k\u1ebft h\u1ee3p nhi\u1ec1u ki\u1ebfn th\u1ee9c li\u00ean quan \u0111\u1ebfn ch\u00fang, trong \u0111\u00f3 t\u00edch v\u00f4 h\u01b0\u1edbng c\u1ee7a hai vect\u01a1 \u1ee9ng d\u1ee5ng quan tr\u1ecdng trong m\u1ed9t s\u1ed1 d\u1ea1ng To\u00e1n nh\u01b0 c\u00e1c b\u00e0i to\u00e1n gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh, b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh, h\u1ec7 ph\u01b0\u01a1ng tr\u00ecnh, hay ch\u00fang minh m\u1ed9t s\u1ed1 \u0111\u1eb3ng th\u1ee9c v\u00e0 b\u1ea5t \u0111\u1eb3ng th\u1ee9c, ho\u0103c c\u00e1c b\u00e0i to\u00e1n v\u1ec1 c\u1ef1c tr\u1ecb.<\/p>\n<p>Xu\u1ea5t ph\u00e1t t\u1eeb t\u1ea7m quan tr\u1ecdng c\u1ee7a n\u1ed9i dung v\u00e0 th\u1ef1c tr\u1ea1ng tr\u00ean, \u0111\u1ec3 <a href=\"https:\/\/www.vietlearn.org\" data-internallinksmanager029f6b8e52c=\"2\" title=\"Vietlearn\" rel=\"nofollow\">h\u1ecdc sinh<\/a> c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng v\u00e0 t\u1ef1 tin h\u01a1n khi g\u1eb7p m\u1ed9t s\u1ed1 b\u00e0i to\u00e1n gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh, b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh, h\u1ec7 ph\u01b0\u01a1ng tr\u00ecnh, hay ch\u00fang minh m\u1ed9t s\u1ed1 b\u1ea5t \u0111\u1eb3ng th\u1ee9c ho\u1eb7c c\u00e1c b\u00e0i to\u00e1n v\u1ec1 c\u1ef1c tr\u1ecb, gi\u00fap c\u00e1c em ph\u00e1t huy \u0111\u01b0\u1ee3c kh\u1ea3 n\u0103ng ph\u00e2n t\u00edch, t\u1ed5ng h\u1ee3p, kh\u00e1i qu\u00e1t h\u00f3a qua c\u00e1c b\u00e0i t\u1eadp nh\u1ecf, c\u00f9ng v\u1edbi s\u1ef1 t\u00edch l\u1ee7y kinh nghi\u1ec7m c\u1ee7a b\u1ea3n th\u00e2n qua nh\u1eefng n\u0103m gi\u1ea3ng d\u1ea1y, t\u00f4i \u0111\u01b0a ra b\u00e0i vi\u1ebft n\u00e0y. Hy v\u1ecdng \u0111\u00f3 l\u00e0 t\u00e0i li\u1ec7u tham kh\u1ea3o nh\u1ecf c\u1ee7a qu\u00fd th\u1ea7y c\u00f4 v\u00e0 c\u00e1c b\u1ea1n <a href=\"https:\/\/www.vietlearn.org\" data-internallinksmanager029f6b8e52c=\"2\" title=\"Vietlearn\" rel=\"nofollow\">h\u1ecdc sinh<\/a>.<\/p>\n<p>\u00a0<\/p>\n<p><strong> I. \u0110\u1ecaNH NGH\u0128A T\u00cdCH V\u00d4 H\u01af\u1edaNG C\u1ee6A HAI V\u00c9CT\u01a0 V\u00c0 \u1ee8NG D\u1ee4NG \u0110\u1ec2 <\/strong><\/p>\n<p><strong> GI\u1ea2I M\u1ed8T S\u1ed0 D\u1ea0NG TO\u00c1N<\/strong><\/p>\n<p>\u00a0<\/p>\n<ol>\n<li><strong>\u0110\u1ecbnh ngh\u0129a:<\/strong><\/li>\n<\/ol>\n<p>Cho hai v\u00e9ct\u01a1 <img decoding=\"async\" width=\"74\" height=\"35\" class=\"wp-image-20416\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_256-13.png\" alt=\"IMG_256\" \/> , t\u00edch v\u00f4 h\u01b0\u1edbng c\u1ee7a hai v\u00e9c t\u01a1 \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a nh\u01b0 sau:<\/p>\n<p><img decoding=\"async\" width=\"187\" height=\"45\" class=\"wp-image-20417\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_257-12.png\" alt=\"IMG_257\" \/> (I), v\u1edbi <img decoding=\"async\" width=\"55\" height=\"37\" class=\"wp-image-20418\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_258-13.png\" alt=\"IMG_258\" \/> l\u00e0 g\u00f3c gi\u1eefa hai v\u00e9ct\u01a1<\/p>\n<p>Suy ra: <img loading=\"lazy\" decoding=\"async\" width=\"154\" height=\"74\" class=\"wp-image-20419\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_259-11.png\" alt=\"IMG_259\" \/><\/p>\n<p>Bi\u1ec3u th\u1ee9c t\u1ecda \u0111\u1ed9 c\u1ee7a t\u00edch v\u00f4 h\u01b0\u1edbng:<\/p>\n<p>&#8211; Trong h\u1ec7 t\u1ecda \u0111\u1ed9 Descartes vu\u00f4ng g\u00f3c Oxy cho <img loading=\"lazy\" decoding=\"async\" width=\"224\" height=\"37\" class=\"wp-image-20420\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_260-13.png\" alt=\"IMG_260\" \/><\/p>\n<p>th\u00ec <img loading=\"lazy\" decoding=\"async\" width=\"167\" height=\"37\" class=\"wp-image-20421\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_261-10.png\" alt=\"IMG_261\" \/><\/p>\n<p>&#8211; Trong h\u1ec7 t\u1ecda \u0111\u1ed9 Descartes vu\u00f4ng g\u00f3c Oxyz cho <img loading=\"lazy\" decoding=\"async\" width=\"282\" height=\"37\" class=\"wp-image-20422\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_262-11.png\" alt=\"IMG_262\" \/><\/p>\n<p>th\u00ec <img loading=\"lazy\" decoding=\"async\" width=\"229\" height=\"37\" class=\"wp-image-20423\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_263-12.png\" alt=\"IMG_263\" \/><\/p>\n<p><strong> 2. \u1ee8ng d\u1ee5ng t\u00edch v\u00f4 h\u01b0\u1edbng c\u1ee7a hai vect\u01a1<\/strong><\/p>\n<p>T\u1eeb c\u00f4ng th\u1ee9c (I) ta c\u00f3 th\u1ec3 v\u1eadn d\u1ee5ng \u0111\u1ec3 ch\u1ee9ng minh hai \u0111\u01b0\u1eddng th\u1eb3ng ho\u1eb7c l\u00e0 song song ho\u1eb7c l\u00e0 vu\u00f4ng g\u00f3c ho\u1eb7c t\u00ednh g\u00f3c t\u1ea1o b\u1edfi hai \u0111\u01b0\u1eddng th\u1eb3ng. Tuy nhi\u00ean, n\u1ebfu d\u1eebng \u1edf \u0111\u00f3 th\u00ec ch\u01b0a th\u1ea5y h\u1ebft \u0111\u01b0\u1ee3c \u1ee9ng d\u1ee5ng c\u1ee7a n\u00f3. Ch\u1ec9 c\u1ea7n ch\u00fa \u00fd r\u1eb1ng <img loading=\"lazy\" decoding=\"async\" width=\"115\" height=\"37\" class=\"wp-image-20424\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_264-11.png\" alt=\"IMG_264\" \/> th\u00ec t\u1eeb (I) ta c\u00f3 th\u1ec3 suy ra c\u00e1c b\u1ea5t \u0111\u1eb3ng th\u1ee9c:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"99\" height=\"45\" class=\"wp-image-20425\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_265-11.png\" alt=\"IMG_265\" \/> (II)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"107\" height=\"45\" class=\"wp-image-20426\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_266-11.png\" alt=\"IMG_266\" \/> (III)<\/p>\n<ul>\n<li>Trong h\u1ec7 t\u1ecda \u0111\u1ed9 Descartes vu\u00f4ng g\u00f3c Oxy cho <img loading=\"lazy\" decoding=\"async\" width=\"224\" height=\"37\" class=\"wp-image-20427\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_267-12.png\" alt=\"IMG_267\" \/> th\u00ec bi\u1ec3u th\u1ee9c gi\u1ea3i t\u00edch c\u1ee7a (II) v\u00e0 (III) l\u00e0<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"320\" height=\"45\" class=\"wp-image-20428\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_268-12.png\" alt=\"IMG_268\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_268-12.png 320w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_268-12-300x42.png 300w\" sizes=\"(max-width: 320px) 100vw, 320px\" \/> (II<sub>1<\/sub>)<\/p>\n<p>\u00a0<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"330\" height=\"45\" class=\"wp-image-20429\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_269-12.png\" alt=\"IMG_269\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_269-12.png 330w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_269-12-300x41.png 300w\" sizes=\"(max-width: 330px) 100vw, 330px\" \/> (III<sub>1<\/sub>)<\/p>\n<p>(II) tr\u1edf th\u00e0nh \u0111\u1eb3ng th\u1ee9c khi <img loading=\"lazy\" decoding=\"async\" width=\"39\" height=\"35\" class=\"wp-image-20430\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_270-10.png\" alt=\"IMG_270\" \/> c\u00f9ng h\u01b0\u1edbng,c\u00f2n (III) khi tr\u1edf th\u00e0nh \u0111\u1eb3ng th\u1ee9c khi <img loading=\"lazy\" decoding=\"async\" width=\"39\" height=\"35\" class=\"wp-image-20431\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_271-12.png\" alt=\"IMG_271\" \/> c\u00f9ng ph\u01b0\u01a1ng,t\u1ee9c l\u00e0 <img loading=\"lazy\" decoding=\"async\" width=\"67\" height=\"32\" class=\"wp-image-20432\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_272-12.png\" alt=\"IMG_272\" \/> hay<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"99\" height=\"72\" class=\"wp-image-20433\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_273-11.png\" alt=\"IMG_273\" \/> (IV<sub>1<\/sub>)<\/p>\n<p>v\u1edbi <img loading=\"lazy\" decoding=\"async\" width=\"59\" height=\"29\" class=\"wp-image-20434\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_274-12.png\" alt=\"IMG_274\" \/> k &gt; 0 khi <img loading=\"lazy\" decoding=\"async\" width=\"39\" height=\"35\" class=\"wp-image-20435\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_275-11.png\" alt=\"IMG_275\" \/> c\u00f9ng h\u01b0\u1edbng, k &lt; 0 khi <img loading=\"lazy\" decoding=\"async\" width=\"39\" height=\"35\" class=\"wp-image-20436\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_276-12.png\" alt=\"IMG_276\" \/> c\u00f9ng ph\u01b0\u01a1ng kh\u00e1c h\u01b0\u1edbng.<\/p>\n<p>\u00a0<\/p>\n<ul>\n<li>Trong h\u1ec7 t\u1ecda \u0111\u1ed9 Descartes vu\u00f4ng g\u00f3c Oxyz cho <img loading=\"lazy\" decoding=\"async\" width=\"282\" height=\"37\" class=\"wp-image-20437\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_277-12.png\" alt=\"IMG_277\" \/> th\u00ec bi\u1ec3u th\u1ee9c gi\u1ea3i t\u00edch c\u1ee7a (II) v\u00e0 (III) l\u00e0<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"472\" height=\"45\" class=\"wp-image-20438\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_278-12.png\" alt=\"IMG_278\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_278-12.png 472w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_278-12-300x29.png 300w\" sizes=\"(max-width: 472px) 100vw, 472px\" \/> (II<sup>\u2019<\/sup>)<\/p>\n<p>\u00a0<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"482\" height=\"45\" class=\"wp-image-20439\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_279-10.png\" alt=\"IMG_279\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_279-10.png 482w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_279-10-300x28.png 300w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_279-10-480x45.png 480w\" sizes=\"(max-width: 482px) 100vw, 482px\" \/> (III<sup>\u2019<\/sup>)<\/p>\n<p>(II) tr\u1edf th\u00e0nh \u0111\u1eb3ng th\u1ee9c khi <img loading=\"lazy\" decoding=\"async\" width=\"39\" height=\"35\" class=\"wp-image-20440\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_280-12.png\" alt=\"IMG_280\" \/> c\u00f9ng h\u01b0\u1edbng,c\u00f2n (III) khi tr\u1edf th\u00e0nh \u0111\u1eb3ng th\u1ee9c khi <img loading=\"lazy\" decoding=\"async\" width=\"39\" height=\"35\" class=\"wp-image-20441\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_281-11.png\" alt=\"IMG_281\" \/> c\u00f9ng ph\u01b0\u01a1ng,t\u1ee9c l\u00e0 <img loading=\"lazy\" decoding=\"async\" width=\"67\" height=\"32\" class=\"wp-image-20442\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_282-12.png\" alt=\"IMG_282\" \/> hay<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"99\" height=\"105\" class=\"wp-image-20443\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_283-11.png\" alt=\"IMG_283\" \/> (IV)<\/p>\n<p>v\u1edbi <img loading=\"lazy\" decoding=\"async\" width=\"59\" height=\"29\" class=\"wp-image-20444\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_284-11.png\" alt=\"IMG_284\" \/> k &gt; 0 khi <img loading=\"lazy\" decoding=\"async\" width=\"39\" height=\"35\" class=\"wp-image-20445\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_285-12.png\" alt=\"IMG_285\" \/> c\u00f9ng h\u01b0\u1edbng, k &lt; 0 khi <img loading=\"lazy\" decoding=\"async\" width=\"39\" height=\"35\" class=\"wp-image-20446\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_286-11.png\" alt=\"IMG_286\" \/> c\u00f9ng ph\u01b0\u01a1ng kh\u00e1c h\u01b0\u1edbng.<\/p>\n<p>C\u00e1c b\u1ea5t \u0111\u1eb3ng th\u1ee9c (II<sup>\u2019<\/sup>), (III<sup>\u2019<\/sup>) g\u1ee3i \u00fd cho ta c\u00f3 th\u1ec3 ch\u1ee9ng minh \u0111\u1eb3ng th\u1ee9c, b\u1ea5t \u0111\u1eb3ng th\u1ee9c, gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh, b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh, h\u1ec7 ph\u01b0\u01a1ng tr\u00ecnh ho\u1eb7c b\u00e0i to\u00e1n c\u1ef1c tr\u1ecb.<\/p>\n<p>\u00a0<\/p>\n<p>I<strong>I. M\u1ed8T S\u1ed0 V\u00cd D\u1ee4 <\/strong><\/p>\n<p><strong>1.\u1ee8ng d\u1ee5ng trong gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh, b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh v\u00e0 h\u1ec7 ph\u01b0\u01a1ng tr\u00ecnh <\/strong><\/p>\n<p><strong> a. Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh <\/strong><\/p>\n<p><strong> V\u00ed d\u1ee5 1<\/strong>: Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"270\" height=\"40\" class=\"wp-image-20447\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_287-12.png\" alt=\"IMG_287\" \/> (1)<\/p>\n<p><strong>L\u1eddi gi\u1ea3i: <\/strong><\/p>\n<p>\u0110K: <img loading=\"lazy\" decoding=\"async\" width=\"97\" height=\"25\" class=\"wp-image-20448\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_288-12.png\" alt=\"IMG_288\" \/><\/p>\n<p>\u0110\u1eb7t <img loading=\"lazy\" decoding=\"async\" width=\"279\" height=\"39\" class=\"wp-image-20449\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_289-13.png\" alt=\"IMG_289\" \/><\/p>\n<p>Khi \u0111\u00f3 <img loading=\"lazy\" decoding=\"async\" width=\"222\" height=\"35\" class=\"wp-image-20450\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_290-12.png\" alt=\"IMG_290\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"475\" height=\"50\" class=\"wp-image-20451\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_291-12.png\" alt=\"IMG_291\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_291-12.png 475w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_291-12-300x32.png 300w\" sizes=\"(max-width: 475px) 100vw, 475px\" \/> .<\/p>\n<p>Do \u0111\u00f3 theo (II<sub>1<\/sub>) th\u00ec ph\u01b0\u01a1ng tr\u00ecnh (1) x\u1ea3y ra khi <img loading=\"lazy\" decoding=\"async\" width=\"170\" height=\"45\" class=\"wp-image-20452\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_292-12.png\" alt=\"IMG_292\" \/> c\u00f9ng ph\u01b0\u01a1ng<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"142\" height=\"69\" class=\"wp-image-20453\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_293-12.png\" alt=\"IMG_293\" \/> (\u0110K: 0&lt; x &lt; 3)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"334\" height=\"142\" class=\"wp-image-20454\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_294-12.png\" alt=\"IMG_294\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_294-12.png 334w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_294-12-300x128.png 300w\" sizes=\"(max-width: 334px) 100vw, 334px\" \/><\/p>\n<p>V\u1edbi nghi\u1ec7m <img loading=\"lazy\" decoding=\"async\" width=\"110\" height=\"37\" class=\"wp-image-20455\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_295-12.png\" alt=\"IMG_295\" \/> &lt; 0 kh\u00f4ng th\u1ecfa m\u00e3n \u0111k<\/p>\n<p>\u00a0<\/p>\n<p><strong>V\u00ed d\u1ee5 2:<\/strong> Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"337\" height=\"40\" class=\"wp-image-20456\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_296-12.png\" alt=\"IMG_296\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_296-12.png 337w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_296-12-300x36.png 300w\" sizes=\"(max-width: 337px) 100vw, 337px\" \/> (2)<\/p>\n<p><strong>L\u1eddi gi\u1ea3i: <\/strong><\/p>\n<p>\u0110\u1eb7t <img loading=\"lazy\" decoding=\"async\" width=\"460\" height=\"44\" class=\"wp-image-20457\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_297-12.png\" alt=\"IMG_297\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_297-12.png 460w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_297-12-300x29.png 300w\" sizes=\"(max-width: 460px) 100vw, 460px\" \/><\/p>\n<p>Ta c\u00f3: <img loading=\"lazy\" decoding=\"async\" width=\"119\" height=\"45\" class=\"wp-image-20458\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_298-12.png\" alt=\"IMG_298\" \/><\/p>\n<p>Ph\u01b0\u01a1ng tr\u00ecnh (2) x\u1ea3y ra khi <img loading=\"lazy\" decoding=\"async\" width=\"112\" height=\"45\" class=\"wp-image-20459\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_299-12.png\" alt=\"IMG_299\" \/> = 3 theo (III<sup>\u2019<\/sup>) v\u00e0 t\u1eeb (IV) ta c\u00f3 h\u1ec7 ph\u01b0\u01a1ng tr\u00ecnh<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"387\" height=\"192\" class=\"wp-image-20460\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_300-12.png\" alt=\"IMG_300\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_300-12.png 387w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_300-12-300x149.png 300w\" sizes=\"(max-width: 387px) 100vw, 387px\" \/><\/p>\n<p><strong>b. Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<\/strong><\/p>\n<p><strong>V\u00ed d\u1ee5 3<\/strong>: Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"337\" height=\"45\" class=\"wp-image-20461\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_301-12.png\" alt=\"IMG_301\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_301-12.png 337w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_301-12-300x40.png 300w\" sizes=\"(max-width: 337px) 100vw, 337px\" \/> (3)<\/p>\n<p><strong>L\u1eddi gi\u1ea3i<\/strong><\/p>\n<p>\u0110K: <img loading=\"lazy\" decoding=\"async\" width=\"49\" height=\"24\" class=\"wp-image-20462\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_302-12.png\" alt=\"IMG_302\" \/><\/p>\n<p>\u0110\u1eb7t <img loading=\"lazy\" decoding=\"async\" width=\"249\" height=\"37\" class=\"wp-image-20463\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_303-12.png\" alt=\"IMG_303\" \/><\/p>\n<p>Ta c\u00f3: <img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"50\" class=\"wp-image-20464\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_304-12.png\" alt=\"IMG_304\" \/><\/p>\n<p>Theo (II<sup>\u2019<\/sup>) ta \u0111\u01b0\u1ee3c: <img loading=\"lazy\" decoding=\"async\" width=\"337\" height=\"45\" class=\"wp-image-20465\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_305-12.png\" alt=\"IMG_305\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_305-12.png 337w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_305-12-300x40.png 300w\" sizes=\"(max-width: 337px) 100vw, 337px\" \/> ,<\/p>\n<p>Suy ra b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh (3) ch\u1ec9 c\u00f3 th\u1ec3 l\u1ea5y d\u1ea5u \u0111\u1eb3ng th\u1ee9c v\u00e0 nh\u1edd (IV) ta \u0111\u01b0\u1ee3c <img loading=\"lazy\" decoding=\"async\" width=\"214\" height=\"34\" class=\"wp-image-20466\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_306-12.png\" alt=\"IMG_306\" \/><\/p>\n<p><strong>V\u00ed d\u1ee5 4<\/strong>: Gi\u1ea3i b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"312\" height=\"34\" class=\"wp-image-20467\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_307-12.png\" alt=\"IMG_307\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_307-12.png 312w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_307-12-300x33.png 300w\" sizes=\"(max-width: 312px) 100vw, 312px\" \/> (4)<\/p>\n<p><strong>L\u1eddi gi\u1ea3i<\/strong><\/p>\n<p>\u0110K: <img loading=\"lazy\" decoding=\"async\" width=\"105\" height=\"60\" class=\"wp-image-20468\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_308-12.png\" alt=\"IMG_308\" \/><\/p>\n<p>\u0110\u1eb7t <img loading=\"lazy\" decoding=\"async\" width=\"389\" height=\"37\" class=\"wp-image-20469\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_309-12.png\" alt=\"IMG_309\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_309-12.png 389w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_309-12-300x29.png 300w\" sizes=\"(max-width: 389px) 100vw, 389px\" \/><\/p>\n<p>Ta c\u00f3: <img loading=\"lazy\" decoding=\"async\" width=\"250\" height=\"45\" class=\"wp-image-20470\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_310-12.png\" alt=\"IMG_310\" \/><\/p>\n<p>Theo (II<sup>\u2019<\/sup>), ta c\u00f3 b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh (2) lu\u00f4n \u0111\u01b0\u1ee3c th\u1ecfa m\u00e3n.<\/p>\n<p>V\u1eady nghi\u1ec7m c\u1ee7a (2) l\u00e0 <img loading=\"lazy\" decoding=\"async\" width=\"105\" height=\"60\" class=\"wp-image-20471\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_311-12.png\" alt=\"IMG_311\" \/><\/p>\n<p><strong>c. Gi\u1ea3i h\u1ec7 ph\u01b0\u01a1ng tr\u00ecnh<\/strong><\/p>\n<p><strong>V\u00ed d\u1ee5 5<\/strong>: Gi\u1ea3i h\u1ec7 ph\u01b0\u01a1ng tr\u00ecnh<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"349\" height=\"132\" class=\"wp-image-20472\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_312-12.png\" alt=\"IMG_312\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_312-12.png 349w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_312-12-300x113.png 300w\" sizes=\"(max-width: 349px) 100vw, 349px\" \/> (5)<\/p>\n<p><strong>L\u1eddi gi\u1ea3i<\/strong><\/p>\n<p>H\u00ea \u0111\u00e3 cho t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"409\" height=\"119\" class=\"wp-image-20473\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_313-12.png\" alt=\"IMG_313\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_313-12.png 409w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_313-12-300x87.png 300w\" sizes=\"(max-width: 409px) 100vw, 409px\" \/><strong><br \/><\/strong>\u0110\u1eb7t <img loading=\"lazy\" decoding=\"async\" width=\"419\" height=\"37\" class=\"wp-image-20474\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_314-12.png\" alt=\"IMG_314\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_314-12.png 419w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_314-12-300x26.png 300w\" sizes=\"(max-width: 419px) 100vw, 419px\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"269\" height=\"42\" class=\"wp-image-20475\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_315-12.png\" alt=\"IMG_315\" \/><\/p>\n<ul>\n<li>N\u1ebfu <img loading=\"lazy\" decoding=\"async\" width=\"225\" height=\"59\" class=\"wp-image-20476\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_316-12.png\" alt=\"IMG_316\" \/><\/li>\n<li>N\u1ebfu <img loading=\"lazy\" decoding=\"async\" width=\"124\" height=\"35\" class=\"wp-image-20477\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_317-12.png\" alt=\"IMG_317\" \/> c\u00f9ng ph\u01b0\u01a1ng <img loading=\"lazy\" decoding=\"async\" width=\"112\" height=\"32\" class=\"wp-image-20478\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_318-12.png\" alt=\"IMG_318\" \/> . X\u00e9t hai tr\u01b0\u1eddng h\u1ee3p <img loading=\"lazy\" decoding=\"async\" width=\"159\" height=\"35\" class=\"wp-image-20479\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_319-12.png\" alt=\"IMG_319\" \/> ta c\u00f3 nghi\u1ec7m c\u1ee7a h\u1ec7 <img loading=\"lazy\" decoding=\"async\" width=\"170\" height=\"59\" class=\"wp-image-20480\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_320-12.png\" alt=\"IMG_320\" \/><\/li>\n<\/ul>\n<p>V\u1eady h\u1ec7 c\u00f3 hai nghi\u1ec7m l\u00e0 <img loading=\"lazy\" decoding=\"async\" width=\"175\" height=\"59\" class=\"wp-image-20481\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_321-11.png\" alt=\"IMG_321\" \/><\/p>\n<p><strong>V\u00ed d\u1ee5 6<\/strong>: Ch\u1ee9ng minh r\u1eb1ng h\u1ec7 sau \u0111\u00e2y v\u00f4 nghi\u1ec7m<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"199\" height=\"85\" class=\"wp-image-20482\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_322-11.png\" alt=\"IMG_322\" \/><\/p>\n<p>\u00a0<\/p>\n<p>\u00a0<\/p>\n<p><strong> L\u1eddi gi\u1ea3i<\/strong><\/p>\n<p>\u0110\u1eb7t <img loading=\"lazy\" decoding=\"async\" width=\"245\" height=\"39\" class=\"wp-image-20483\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_323-11.png\" alt=\"IMG_323\" \/><\/p>\n<p>Ta c\u00f3: <img loading=\"lazy\" decoding=\"async\" width=\"157\" height=\"45\" class=\"wp-image-20484\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_324-11.png\" alt=\"IMG_324\" \/><\/p>\n<p>Theo h\u1ec7 tr\u00ean, ta c\u00f3 <img loading=\"lazy\" decoding=\"async\" width=\"239\" height=\"39\" class=\"wp-image-20485\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_325-11.png\" alt=\"IMG_325\" \/> v\u00e0 <img loading=\"lazy\" decoding=\"async\" width=\"120\" height=\"35\" class=\"wp-image-20486\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_326-11.png\" alt=\"IMG_326\" \/> .<\/p>\n<p>Do \u0111\u00f3 <img loading=\"lazy\" decoding=\"async\" width=\"105\" height=\"45\" class=\"wp-image-20487\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_327-11.png\" alt=\"IMG_327\" \/> \u0111i\u1ec1u n\u00e0y m\u00e2u thu\u1eabn v\u1edbi (II).<\/p>\n<p>V\u1eady h\u1ec7 tr\u00ean v\u00f4 nghi\u1ec7m.<\/p>\n<p>\u00a0<\/p>\n<p><strong>2.<\/strong> <strong>\u1ee8ng d\u1ee5ng trong ch\u1ee9ng minh \u0111\u1eb3ng th\u1ee9c v\u00e0 b\u1ea5t \u0111\u1eb3ng th\u1ee9c <\/strong><\/p>\n<p><strong>a. Ch\u1ee9ng minh b\u1ea5t \u0111\u1eb3ng th\u1ee9c <\/strong><\/p>\n<p><strong>V\u00ed d\u1ee5 1: <\/strong> Ch\u1ee9ng minh r\u1eb1ng v\u1edbi m\u1ecdi a, b, c ta c\u00f3<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"265\" height=\"39\" class=\"wp-image-20488\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_328-10.png\" alt=\"IMG_328\" \/> (*)<\/p>\n<p><strong>L\u1eddi gi\u1ea3i<\/strong><\/p>\n<p>Khai tri\u1ec3n v\u1ebf tr\u00e1i: VT = a<sup>2<\/sup>bc + ab<sup>2<\/sup>c + abc<sup>2<\/sup><\/p>\n<p>\u0110\u1eb7t <img loading=\"lazy\" decoding=\"async\" width=\"279\" height=\"37\" class=\"wp-image-20489\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_329-10.png\" alt=\"IMG_329\" \/><\/p>\n<p>Ta c\u00f3: <img loading=\"lazy\" decoding=\"async\" width=\"244\" height=\"105\" class=\"wp-image-20490\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_330-10.png\" alt=\"IMG_330\" \/><\/p>\n<p>\u00c1p d\u1ee5ng (II) ta \u0111\u01b0\u1ee3c: <img loading=\"lazy\" decoding=\"async\" width=\"329\" height=\"39\" class=\"wp-image-20491\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_331-10.png\" alt=\"IMG_331\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_331-10.png 329w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_331-10-300x36.png 300w\" sizes=\"(max-width: 329px) 100vw, 329px\" \/> (*)<\/p>\n<p>L\u1ea1i \u0111\u1eb7t <img loading=\"lazy\" decoding=\"async\" width=\"285\" height=\"39\" class=\"wp-image-20492\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_332-10.png\" alt=\"IMG_332\" \/><\/p>\n<p>\u00c1p d\u1ee5ng (II) m\u1ed9t l\u1ea7n n\u1eefa ta \u0111\u01b0\u1ee3c <img loading=\"lazy\" decoding=\"async\" width=\"315\" height=\"34\" class=\"wp-image-20493\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/12\/img_333-10.png\" alt=\"IMG_333\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_333-10.png 315w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/12\/img_333-10-300x32.png 300w\" sizes=\"(max-width: 315px) 100vw, 315px\" \/> (**)<\/p>\n<p>T\u1eeb (*) v\u00e0 (**) suy ra (1)<\/p>\n<p>Theo (IV), d\u1ec5 th\u1ea5y b\u1ea5t \u0111\u1eb3ng th\u1ee9c tr\u1edf th\u00e0nh \u0111\u1eb3ng th\u1ee9c khi a = b = c.<\/p>","protected":false},"excerpt":{"rendered":"<p>T\u00edch v\u00f4 h\u01b0\u1edbng c\u1ee7a hai vect\u01a1 m\u1ed9t ph\u1ea7n nh\u1ecf trong ch\u01b0\u01a1ng tr\u00ecnh H\u00ecnh h\u1ecdc 10. Tuy v\u1eady t\u00edch v\u00f4 h\u01b0\u1edbng c\u1ee7a hai vec t\u01a1 \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng trong H\u00ecnh h\u1ecdc n\u00f3i ri\u00eang v\u00e0 trong to\u00e1n h\u1ecdc n\u00f3i chung. Trong c\u00e1c k\u00ec thi ta th\u01b0\u1eddng th\u1ea5y xu\u1ea5t hi\u1ec7n m\u1ed9t s\u1ed1 b\u00e0i to\u00e1n gi\u1ea3i ph\u01b0\u01a1ng [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[41],"tags":[],"class_list":["post-20415","post","type-post","status-publish","format-standard","hentry","category-toan-lop-10"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/20415","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/comments?post=20415"}],"version-history":[{"count":1,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/20415\/revisions"}],"predecessor-version":[{"id":20494,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/20415\/revisions\/20494"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=20415"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=20415"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=20415"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}