{"id":1035,"date":"2021-10-08T13:04:43","date_gmt":"2021-10-08T13:04:43","guid":{"rendered":"https:\/\/www.vietlearn.org\/post\/?p=1035"},"modified":"2021-10-15T16:00:52","modified_gmt":"2021-10-15T09:00:52","slug":"cong-thuc-nghiem-cua-phuong-trinh-bac-2-va-cach-giai-cac-dang-bai-tap","status":"publish","type":"post","link":"https:\/\/www.vietlearn.org\/kien-thuc\/cong-thuc-nghiem-cua-phuong-trinh-bac-2-va-cach-giai-cac-dang-bai-tap\/","title":{"rendered":"C\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 v\u00e0 c\u00e1ch gi\u1ea3i c\u00e1c d\u1ea1ng b\u00e0i t\u1eadp"},"content":{"rendered":"\n<script type=\"text\/javascript\">\nimg_numb = 10;\n<\/script>\n\n\n\n<p class=\"wp-block-paragraph\">Ghi ch\u00fa: T\u00e0i li\u1ec7u tr\u00edch d\u1eabn<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 l\u00e0 m\u1ed9t trong nh\u1eefng chuy\u00ean \u0111\u1ec1 quan tr\u1ecdng c\u1ee7a to\u00e1n l\u1edbp 9. \u0110\u00e2y l\u00e0 chuy\u00ean \u0111\u1ec1 kh\u00f4ng qu\u00e1 ph\u1ee9c t\u1ea1p nh\u01b0ng l\u1ea1i c\u00f3 nhi\u1ec1u d\u1ea1ng b\u00e0i t\u1eadp. N\u1ebfu kh\u00f4ng hi\u1ec3u r\u00f5 l\u00fd thuy\u1ebft, b\u1ea1n s\u1ebd kh\u00f4ng th\u1ec3 l\u00e0m \u0111\u00fang c\u00e1c d\u1ea1ng b\u00e0i t\u1eadp. V\u1eady b\u1ea1n \u0111\u00e3 bi\u1ebft c\u00f4ng th\u1ee9c gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 v\u00e0 c\u00e1c d\u1ea1ng b\u00e0i t\u1eadp li\u00ean quan ch\u01b0a? H\u00e3y c\u00f9ng Vietlearn t\u00ecm hi\u1ec3u chi ti\u1ebft qua b\u00e0i vi\u1ebft d\u01b0\u1edbi \u0111\u00e2y.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 l\u00e0 g\u00ec?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1edbc khi t\u00ecm hi\u1ec3u c\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2, ch\u00fang ta c\u1ea7n hi\u1ec3u ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 l\u00e0 g\u00ec, c\u00f3 d\u1ea1ng th\u1ebf n\u00e0o. Ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc hai hay c\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc hai 1 \u1ea9n. \u0110\u00e2y l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh g\u1ed3m 1 \u1ea9n s\u1ed1, \u0111\u01b0\u1ee3c t\u1ed5ng qu\u00e1t d\u01b0\u1edbi d\u1ea1ng:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">ax<sup>2<\/sup> + bx +c = 0 (a \u22600)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Trong \u0111\u00f3: a, b, c l\u00e0 c\u00e1c s\u1ed1 th\u1ef1c \u0111\u01b0\u1ee3c cho tr\u01b0\u1edbc, x l\u00e0 \u1ea9n s\u1ed1 ph\u1ea3i \u0111i t\u00ecm v\u00e0 a ph\u1ea3i l\u00e0 m\u1ed9t s\u1ed1 kh\u00e1c 0. B\u1edfi n\u1ebfu a = 0 th\u00ec ph\u01b0\u01a1ng tr\u00ecnh tr\u00ean s\u1ebd tr\u1edf v\u1ec1 ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 1 c\u00f3 m\u1ed9t \u1ea9n s\u1ed1.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">V\u1edbi d\u1ea1ng ph\u01b0\u01a1ng tr\u00ecnh n\u00e0y s\u1ebd c\u00f3 nhi\u1ec1u d\u1ea1ng b\u00e0i t\u1eadp kh\u00e1c nhau. Tuy nhi\u00ean, nh\u00ecn chung, c\u00e1c d\u1ea1ng b\u00e0i t\u1eadp \u0111\u1ec1u quy v\u1ec1 vi\u1ec7c t\u00ecm nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh cho tr\u01b0\u1edbc. T\u1eadp nghi\u1ec7m c\u00f3 th\u1ec3 g\u1ed3m 1 ho\u1eb7c nhi\u1ec1u nghi\u1ec7m, mi\u1ec5n sao th\u1ecfa m\u00e3n ph\u01b0\u01a1ng tr\u00ecnh.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img fetchpriority=\"high\" decoding=\"async\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/10\/unnamed-3.jpg\" alt=\"C\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2\" class=\"wp-image-2804\" width=\"712\" height=\"412\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/10\/unnamed-3.jpg 512w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/10\/unnamed-3-300x173.jpg 300w\" sizes=\"(max-width: 712px) 100vw, 712px\" \/><figcaption>C\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 l\u00e0 m\u1ed9t d\u1ea1ng b\u00e0i t\u1eadp quan tr\u1ecdng trong to\u00e1n 9<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Sau khi \u0111\u00e3 t\u00ecm hi\u1ec3u v\u1ec1 ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2, ch\u1eafc h\u1eb3n b\u1ea1n \u0111ang th\u1eafc m\u1eafc c\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 th\u1ebf n\u00e0o. C\u00f4ng th\u1ee9c gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 d\u1ea1ng ax<sup>2<\/sup> + bx +c = 0 (a \u22600) c\u00f3 \u0394 = b<sup>2<\/sup> \u2013 4ac s\u1ebd c\u00f3 3 tr\u01b0\u1eddng h\u1ee3p:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0394 = 0: khi \u0111\u00f3 ph\u01b0\u01a1ng tr\u00ecnh s\u1ebd c\u00f3 nghi\u1ec7m k\u00e9p hay c\u00f2n g\u1ecdi l\u00e0 2 nghi\u1ec7m.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0394 &gt; 0 th\u00ec c\u00f3 2 nghi\u1ec7m kh\u00e1c nhau l\u00e0 x1 v\u00e0 x2, \u0111\u01b0\u1ee3c t\u00ednh theo c\u00f4ng th\u1ee9c (\u2212b+\/-\u221a \u0394)\/2a.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1eddng h\u1ee3p \u0394 &lt; 0 th\u00ec ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 k\u1ec3 tr\u00ean v\u00f4 nghi\u1ec7m, t\u1ee9c l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh kh\u00f4ng c\u00f3 s\u1ed1 n\u00e0o th\u1ecfa m\u00e3n \u0111\u1ec3 2 v\u1ebf b\u1eb1ng nhau.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Trong tr\u01b0\u1eddng h\u1ee3p 2 s\u1ed1 th\u1ef1c a,c tr\u00e1i d\u1ea5u th\u00ec ph\u01b0\u01a1ng tr\u00ecnh s\u1ebd lu\u00f4n c\u00f3 2 nghi\u1ec7m ph\u00e2n bi\u1ec7t nhau, t\u1ee9c l\u00e0 \u0394 &gt; 0.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D\u1ea1ng c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ecbnh l\u00fd Viet trong ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Nh\u1eafc t\u1edbi ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 v\u00e0 c\u00f4ng th\u1ee9c gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2, ch\u00fang ta kh\u00f4ng th\u1ec3 kh\u00f4ng nh\u1eafc t\u1edbi \u0111\u1ecbnh l\u00fd Viet. \u0110\u00e2y l\u00e0 m\u1ed9t \u0111\u1ecbnh l\u00fd quan tr\u1ecdng, li\u00ean quan t\u1edbi nhi\u1ec1u d\u1ea1ng b\u00e0i t\u1eadp c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Nh\u01b0 \u0111\u00e3 gi\u1edbi thi\u1ec7u \u1edf tr\u00ean, ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 c\u00f3 d\u1ea1ng: ax2 + bx +c = 0 (a \u22600) s\u1ebd c\u00f3 t\u1ed1i \u0111a 2 nghi\u1ec7m, g\u1ecdi l\u00e0 x1 v\u00e0 x2. Khi \u0111\u00f3, x<sub>1<\/sub> v\u00e0 x<sub>2<\/sub> s\u1ebd th\u1ecfa m\u00e3n \u0111\u1ed3ng th\u1eddi c\u1ea3 2 \u0111i\u1ec1u ki\u1ec7n, \u0111\u00f3 l\u00e0:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">x<sub>1<\/sub> + x<sub>2<\/sub> = -b\/a<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">x<sub>1<\/sub>x<sub>2<\/sub> = c\/a<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Khi l\u00e0m b\u00e0i t\u1eadp v\u1ec1 ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2, b\u1ea1n c\u00f3 th\u1ec3 \u00e1p d\u1ee5ng \u0111\u1ecbnh l\u00fd viet b\u1eb1ng c\u00e1ch bi\u1ebfn \u0111\u1ed5i bi\u1ec3u th\u1ee9c \u0111\u1ec3 xu\u1ea5t hi\u1ec7n x1 + x<sub>2<\/sub> v\u00e0 x<sub>1<\/sub>x<sub>2<\/sub>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B\u1ea1n c\u0169ng c\u00f3 th\u1ec3 \u00e1p d\u1ee5ng \u0111\u1ecbnh l\u00fd Viet \u0111\u1ea3o v\u1edbi 2 s\u1ed1 x1 v\u00e0 x2 th\u1ecfa m\u00e3n 2 \u0111i\u1ec1u ki\u1ec7n:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">x<sub>1<\/sub> + x<sub>2<\/sub> = S<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">x<sub>1<\/sub>x<sub>2<\/sub> = P<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Trong \u0111\u00f3: c\u1ea3 x1 v\u00e0 x2 \u0111\u1ec1u l\u00e0 nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh x<sup>2<\/sup> \u2013 Sx + P = 0.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Nh\u1eafc t\u1edbi \u0111\u1ecbnh l\u00fd Viet, ch\u00fang ta kh\u00f4ng th\u1ec3 b\u1ecf qua \u1ee9ng d\u1ee5ng c\u1ee7a \u0111\u1ecbnh l\u00fd n\u00e0y. V\u1edbi ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2, b\u1ea1n c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng t\u00ednh \u0111\u01b0\u1ee3c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh m\u00e0 kh\u00f4ng c\u1ea7n \u00e1p d\u1ee5ng c\u00f4ng th\u1ee9c t\u00ednh nghi\u1ec7m v\u1edbi m\u1ed9t s\u1ed1 tr\u01b0\u1eddng h\u1ee3p \u0111\u1eb7c bi\u1ec7t:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1eddng h\u1ee3p 1: a+b+c=0 th\u00ec ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 2 nghi\u1ec7m l\u00e0 x<sub>1<\/sub> = 1 v\u00e0 x<sub>2<\/sub> = c\/a.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1eddng h\u1ee3p 2: a-b+c=0 th\u00ec ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 2 nghi\u1ec7m l\u00e0 x<sub>1<\/sub> = -1 v\u00e0 x<sub>2<\/sub> = -c\/a. (\u0110\u00e2y l\u00e0 tr\u01b0\u1eddng h\u1ee3p ng\u01b0\u1ee3c l\u1ea1i c\u1ee7a tr\u01b0\u1eddng h\u1ee3p 1, b\u1ea1n c\u1ea7n nh\u00ecn k\u1ef9 d\u1ea5u \u0111\u1ec3 tr\u00e1nh nh\u1ea7m l\u1eabn).<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"800\" height=\"500\" src=\"https:\/\/www.vietlearn.org\/post\/wp-content\/uploads\/2021\/10\/cong-thuc-tinh-delta-delta-phay-phuong-trinh-bac-2-bai-tap-2.jpg\" alt=\"C\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2\" class=\"wp-image-2806\" srcset=\"https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/10\/cong-thuc-tinh-delta-delta-phay-phuong-trinh-bac-2-bai-tap-2.jpg 800w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/10\/cong-thuc-tinh-delta-delta-phay-phuong-trinh-bac-2-bai-tap-2-300x188.jpg 300w, https:\/\/www.vietlearn.org\/kien-thuc\/wp-content\/uploads\/2021\/10\/cong-thuc-tinh-delta-delta-phay-phuong-trinh-bac-2-bai-tap-2-768x480.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><figcaption>C\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 c\u00f3 c\u00e1c d\u1ea1ng b\u00e0i t\u1eadp quan tr\u1ecdng<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D\u1ea1ng b\u00e0i t\u1eadp \u1ee9ng d\u1ee5ng c\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Sau khi t\u00ecm hi\u1ec3u c\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2, b\u1ea1n c\u1ea7n l\u01b0u \u00fd t\u1edbi c\u00e1c d\u1ea1ng b\u00e0i t\u1eadp. M\u1ed7i d\u1ea1ng b\u00e0i t\u1eadp s\u1ebd c\u00f3 m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p gi\u1ea3i kh\u00e1c nhau. \u00c1p d\u1ee5ng \u0111\u00fang ph\u01b0\u01a1ng ph\u00e1p s\u1ebd gi\u00fap b\u1ea1n ti\u1ebft ki\u1ec7m th\u1eddi gian v\u00e0 gi\u1ea3i b\u00e0i t\u1eadp ch\u00ednh x\u00e1c h\u01a1n.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C\u1ee5 th\u1ec3, hi\u1ec7n nay ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 c\u00f3 c\u00e1c d\u1ea1ng b\u00e0i t\u1eadp ch\u1ee7 y\u1ebfu nh\u01b0:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D\u1ea1ng 1: ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 m\u1ed9t \u1ea9n kh\u00f4ng c\u00f3 tham s\u1ed1<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ec3 gi\u1ea3i d\u1ea1ng b\u00e0i t\u1eadp n\u00e0y, b\u1ea1n c\u1ea7n \u00e1p d\u1ee5ng c\u00f4ng th\u1ee9c \u0394 v\u00e0 \u0394\u2019 r\u1ed3i \u00e1p d\u1ee5ng c\u00e1c c\u00f4ng th\u1ee9c t\u00ednh ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 \u0111\u00e3 \u0111\u01b0\u1ee3c gi\u1edbi thi\u1ec7u \u1edf tr\u00ean. Qua \u0111\u00f3 t\u00ecm \u0111\u01b0\u1ee3c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">V\u00ed d\u1ee5: ta c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh: x<sup>2<\/sup>-3x+2=0. \u00c1p d\u1ee5ng c\u00f4ng th\u1ee9c t\u00ednh \u0394, ta s\u1ebd c\u00f3 \u0394 = 1. V\u1eady 2 nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh s\u1ebd l\u1ea7n l\u01b0\u1ee3t l\u00e0:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D\u1ea1ng 2: ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 m\u1ed9t \u1ea9n c\u00f3 tham s\u1ed1<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B\u00ean c\u1ea1nh d\u1ea1ng kh\u00f4ng ch\u1ee9a tham s\u1ed1, ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 m\u1ed9t \u1ea9n c\u00f3 tham s\u1ed1 c\u0169ng l\u00e0 m\u1ed9t d\u1ea1ng b\u00e0i t\u1eadp quan tr\u1ecdng. \u0110\u1ec3 gi\u1ea3i d\u1ea1ng b\u00e0i t\u1eadp n\u00e0y, b\u1ea1n c\u0169ng c\u1ea7n s\u1eed d\u1ee5ng c\u00f4ng th\u1ee9c t\u00ednh \u0394. T\u1eeb \u0111\u00f3, d\u1ef1a v\u00e0o 3 tr\u01b0\u1eddng h\u1ee3p c\u1ee7a \u0394 \u0111\u00e3 \u0111\u01b0\u1ee3c gi\u1ea3i th\u00edch \u1edf tr\u00ean, b\u1ea1n c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c ph\u01b0\u01a1ng tr\u00ecnh c\u00f3 nghi\u1ec7m k\u00e9p, c\u00f3 2 nghi\u1ec7m ph\u00e2n bi\u1ec7t hay v\u00f4 nghi\u1ec7m. T\u1eeb \u0111\u00f3 \u00e1p d\u1ee5ng c\u00f4ng th\u1ee9c \u0111\u1ec3 t\u00ednh \u0111\u01b0\u1ee3c c\u00e1c gi\u00e1 tr\u1ecb nghi\u1ec7m c\u1ee5 th\u1ec3.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u00ean \u0111\u00e2y l\u00e0 c\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 v\u00e0 c\u00e1ch gi\u1ea3i m\u1ed9t s\u1ed1 d\u1ea1ng b\u00e0i t\u1eadp c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2. H\u00e3y ghi nh\u1edb c\u00e1c c\u00f4ng th\u1ee9c, d\u1ea1ng b\u00e0i t\u1eadp \u0111\u1ec3 c\u00f3 th\u1ec3 \u00e1p d\u1ee5ng khi g\u1eb7p d\u1ea1ng b\u00e0i t\u1eadp n\u00e0y nh\u00e9.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe title=\"To\u00e1n h\u1ecdc l\u1edbp 9 - B\u00e0i 4 - C\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc hai - ti\u1ebft 1\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/hYso8UYp2AU?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"<p>Ghi ch\u00fa: T\u00e0i li\u1ec7u tr\u00edch d\u1eabn C\u00f4ng th\u1ee9c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc 2 l\u00e0 m\u1ed9t trong nh\u1eefng chuy\u00ean \u0111\u1ec1 quan tr\u1ecdng c\u1ee7a to\u00e1n l\u1edbp 9. \u0110\u00e2y l\u00e0 chuy\u00ean \u0111\u1ec1 kh\u00f4ng qu\u00e1 ph\u1ee9c t\u1ea1p nh\u01b0ng l\u1ea1i c\u00f3 nhi\u1ec1u d\u1ea1ng b\u00e0i t\u1eadp. N\u1ebfu kh\u00f4ng hi\u1ec3u r\u00f5 l\u00fd thuy\u1ebft, b\u1ea1n s\u1ebd kh\u00f4ng th\u1ec3 l\u00e0m \u0111\u00fang c\u00e1c d\u1ea1ng [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":2802,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[9],"tags":[],"class_list":["post-1035","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-toan-hoc"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/1035","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=1035"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/1035\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media\/2802"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=1035"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=1035"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=1035"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}