{"id":991,"date":"2021-10-08T12:59:00","date_gmt":"2021-10-08T12:59:00","guid":{"rendered":"https:\/\/www.vietlearn.org\/post\/?p=991"},"modified":"2021-10-14T22:11:35","modified_gmt":"2021-10-14T15:11:35","slug":"tu-giac-noi-tiep-duong-tron-hoc-tot-toan-9-cung-toppy","status":"publish","type":"post","link":"https:\/\/www.vietlearn.org\/kien-thuc\/tu-giac-noi-tiep-duong-tron-hoc-tot-toan-9-cung-toppy\/","title":{"rendered":"T\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n \u2013 H\u1ecdc t\u1ed1t To\u00e1n 9"},"content":{"rendered":"\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\">T\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n l\u00e0 m\u1ed9t trong nh\u1eefng ch\u01b0\u01a1ng tr\u00ecnh h\u00ecnh h\u1ecdc l\u1edbp 9 v\u00f4 c\u00f9ng quan tr\u1ecdng v\u00e0 lu\u00f4n b\u1eaft g\u1eb7p trong nh\u1eefng k\u1ef3 thi. \u0110\u1ec3 hi\u1ec3u \u0111\u01b0\u1ee3c r\u00f5 h\u01a1n v\u1ec1 \u0111\u1ecbnh ngh\u0129a, c\u00e1c \u0111\u1ecbnh l\u00fd, c\u00e1ch ch\u1ee9ng minh c\u0169ng nh\u01b0 c\u00e1c b\u00e0i to\u00e1n v\u1ec1 ch\u1ee9ng minh t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n. H\u00e3y c\u00f9ng https::\/\/toppy.vn\/ t\u00ecm hi\u1ec3u qua b\u00e0i gi\u1ea3ng chi ti\u1ebft ngay sau \u0111\u00e2y.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">I. L\u00fd thuy\u1ebft t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n:<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u0110\u1ecbnh ngh\u0129a<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n l\u00e0 t\u1ee9 gi\u00e1c c\u00f3 4 \u0111\u1ec9nh n\u1eb1m tr\u00ean c\u00f9ng 1 \u0111\u01b0\u1eddng tr\u00f2n.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ecbnh ngh\u0129a v\u1ec1 t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n<\/p>\n\n\n\n<ol class=\"wp-block-list\" start=\"2\"><li>\u0110\u1ecbnh l\u00ed:<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ecbnh l\u00fd:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Trong 1 t\u1ee9 gi\u00e1c n\u1eb1m trong \u0111\u01b0\u1eddng tr\u00f2n, t\u1ed5ng s\u1ed1 \u0111o c\u1ee7a 2 g\u00f3c \u0111\u1ed1i di\u1ec7n l\u00e0 b\u1eb1ng nhau.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">V\u00ed d\u1ee5 minh h\u1ecda:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cho 1 \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m O, b\u00e1n k\u00ednh R (O,R) c\u00f3 t\u1ee9 gi\u00e1c ABCD n\u1ed9i ti\u1ebfp<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u21d2 Ta c\u00f3 g\u00f3c A + g\u00f3c C= 180\u00ba v\u00e0 g\u00f3c B + g\u00f3c D= 180\u00ba<\/p>\n\n\n\n<ol class=\"wp-block-list\" start=\"3\"><li>\u0110\u1ecbnh l\u00ed \u0111\u1ea3o:<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">N\u1ebfu 1 t\u1ee9 gi\u00e1c m\u00e0 c\u00f3 t\u1ed5ng s\u1ed1 c\u1ee7a \u0111o 2 g\u00f3c \u0111\u1ed1i di\u1ec7n l\u00e0 180\u00ba th\u00ec t\u1ee9 gi\u00e1c \u0111\u00f3 l\u00e0 t\u1ee9 gi\u00e1c n\u1eb1m trong \u0111\u01b0\u1eddng tr\u00f2n.<\/p>\n\n\n\n<ol class=\"wp-block-list\" start=\"4\"><li>1 s\u1ed1 d\u1ea5u hi\u1ec7u \u0111\u1ec3 nh\u1eadn bi\u1ebft:<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ec3 nh\u1eadn bi\u1ebft v\u00e0 ch\u1ee9ng minh t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n c\u1ea7n d\u1ef1a v\u00e0o m\u1ed9t s\u1ed1 d\u1ea5u hi\u1ec7u sau:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c c\u00f3 t\u1ed5ng c\u1ee7a 2 g\u00f3c \u0111\u1ed1i l\u00e0 180\u00ba<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c m\u00e0 c\u00f3 g\u00f3c ngo\u00e0i c\u1ee7a 1 \u0111\u1ec9nh b\u1eb1ng v\u1edbi g\u00f3c trong c\u1ee7a \u0111\u1ec9nh \u0111\u1ed1i v\u1edbi n\u00f3<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c m\u00e0 c\u00f3 4 \u0111\u1ec9nh \u0111\u1ec1u c\u00e1ch \u0111\u1ec1u 1 \u0111i\u1ec3m (c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c). \u0110i\u1ec3m \u0111\u00f3 th\u00f4ng th\u01b0\u1eddng s\u1ebd l\u00e0 t\u00e2m c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n ngo\u1ea1i ti\u1ebfp.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c m\u00e0 c\u00f3 2 \u0111\u1ec9nh k\u1ec1 v\u1edbi nhau v\u00e0 c\u00f9ng nh\u00ecn c\u1ea1nh ch\u1ee9a 2 \u0111\u1ec9nh c\u00f2n l\u1ea1i c\u00f9ng 1 g\u00f3c \u03b1.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">II. C\u00e1c c\u00e1ch ch\u1ee9ng minh:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D\u1ef1a v\u00e0o \u0111\u1ecbnh ngh\u0129a, c\u00e1c \u0111\u1ecbnh l\u00fd v\u00e0 m\u1ed9t s\u1ed1 d\u1ea5u hi\u1ec7u nh\u1eadn bi\u1ebft t\u1ee9 gi\u00e1c n\u1eb1m trong \u0111\u01b0\u1eddng tr\u00f2n, d\u01b0\u1edbi \u0111\u00e2y l\u00e0 t\u1ed5ng h\u1ee3p c\u00e1c c\u00e1ch ch\u1ee9ng minh t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">6 c\u00e1ch ch\u1ee9ng minh t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>Ch\u1ee9ng minh 4 \u0111\u1ec9nh c\u1ee7a t\u1ee9 gi\u00e1c n\u1eb1m c\u00e1ch \u0111\u1ec1u 1 \u0111i\u1ec3m n\u00e0o \u0111\u00f3.<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">X\u00e9t t\u1ee9 gi\u00e1c ABCD v\u00e0 1 \u0111i\u1ec3m I:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c ABCD \u0111\u01b0\u1ee3c xem l\u00e0 t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m I, b\u00e1n k\u00ednh R (I,R) khi v\u00e0 ch\u1ec9 khi: IA = IB = IC = ID.<\/p>\n\n\n\n<ol class=\"wp-block-list\" start=\"2\"><li>Ch\u1ee9ng minh t\u1ed5ng 2 g\u00f3c \u0111\u1ed1i c\u1ee7a t\u1ee9 gi\u00e1c l\u00e0 180\u00ba<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">X\u00e9t t\u1ee9 gi\u00e1c ABCD:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c ABCD \u0111\u01b0\u1ee3c xem l\u00e0 t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n n\u1ebfu nh\u01b0 A +C= 180\u00ba v\u00e0 B + D= 180\u00ba<\/p>\n\n\n\n<ol class=\"wp-block-list\" start=\"3\"><li>Ch\u1ee9ng minh 2 \u0111\u1ec9nh k\u1ec1 1 c\u1ea1nh c\u00f9ng nh\u00ecn c\u1ea1nh d\u01b0\u1edbi v\u1edbi 2 g\u00f3c \u0111\u1ec1u b\u1eb1ng nhau:<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">X\u00e9t t\u1ee9 gi\u00e1c ABCD:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c ABCD \u0111\u01b0\u1ee3c xem l\u00e0 t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n khi v\u00e0 ch\u1ec9 khi ta c\u00f3 g\u00f3c DAC = g\u00f3c DBC v\u00e0 c\u00f9ng ch\u1eafn cung DC.<\/p>\n\n\n\n<ol class=\"wp-block-list\" start=\"4\"><li>N\u1ebfu nh\u01b0 1 t\u1ee9 gi\u00e1c m\u00e0 t\u1ed5ng s\u1ed1 \u0111o c\u1ee7a 2 g\u00f3c \u0111\u1ed1i b\u1eb1ng nhau th\u00ec \u0111\u00f3 l\u00e0 t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n.<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">X\u00e9t t\u1ee9 gi\u00e1c ABCD:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c ABCD \u0111\u01b0\u1ee3c xem l\u00e0 t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n khi v\u00e0 ch\u1ec9 khi ta c\u00f3 g\u00f3c A + g\u00f3c C= g\u00f3c B + g\u00f3c D= \u03b1. \u0110\u00e2y ch\u00ednh l\u00e0 tr\u01b0\u1eddng h\u1ee3p \u0111\u1eb7c bi\u1ec7t c\u1ee7a c\u00e1ch ch\u1ee9ng minh t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n th\u1ee9 2.<\/p>\n\n\n\n<ol class=\"wp-block-list\" start=\"5\"><li>T\u1ee9 gi\u00e1c m\u00e0 c\u00f3 g\u00f3c ngo\u00e0i c\u1ee7a 1 \u0111\u1ec9nh b\u1eb1ng v\u1edbi g\u00f3c trong c\u1ee7a \u0111\u1ec9nh \u0111\u1ed1i v\u1edbi n\u00f3 th\u00ec n\u1ed9i ti\u1ebfp trong \u0111\u01b0\u1eddng tr\u00f2n.<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">X\u00e9t t\u1ee9 gi\u00e1c ABCD:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c ABCD \u0111\u01b0\u1ee3c xem l\u00e0 t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n khi g\u00f3c ngo\u00e0i c\u1ee7a \u0111\u1ec9nh A b\u1eb1ng v\u1edbi g\u00f3c C, ho\u1eb7c c\u0169ng c\u00f3 th\u1ec3 l\u00e0 g\u00f3c ngo\u00e0i c\u1ee7a \u0111\u1ec9nh B b\u1eb1ng v\u1edbi g\u00f3c D.<\/p>\n\n\n\n<ol class=\"wp-block-list\" start=\"6\"><li>Ch\u1ee9ng minh v\u1edbi ph\u01b0\u01a1ng ph\u00e1p ph\u1ea3n ch\u1ee9ng:<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed1i v\u1edbi c\u00e1ch ch\u1ee9ng minh t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n n\u00e0y th\u00ec s\u1ebd ch\u1ee9ng minh t\u1ee9 gi\u00e1c l\u00e0 nh\u1eefng h\u00ecnh \u0111\u1eb7c bi\u1ec7t nh\u01b0 h\u00ecnh ch\u1eef nh\u1eadt, h\u00ecnh vu\u00f4ng, h\u00ecnh b\u00ecnh h\u00e0nh ho\u1eb7c h\u00ecnh thoi.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">III. C\u00e1c b\u00e0i to\u00e1n v\u1ec1 ch\u1ee9ng minh t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n \u0111\u01b0\u1ee3c xem l\u00e0 m\u1ed9t trong nh\u1eefng ki\u1ebfn th\u1ee9c v\u00f4 c\u00f9ng quan tr\u1ecdng, kh\u00f4ng th\u1ec3 thi\u1ebfu trong nh\u1eefng b\u00e0i ki\u1ec3m tra. Ch\u00ednh v\u00ec v\u1eady \u0111\u1ec3 c\u1ee7ng c\u1ed1 l\u1ea1i ki\u1ebfn th\u1ee9c l\u00fd thuy\u1ebft c\u0169ng nh\u01b0 c\u00e1c c\u00e1ch ch\u1ee9ng minh, d\u01b0\u1edbi \u0111\u00e2y l\u00e0 c\u00e1c b\u00e0i to\u00e1n v\u1ec1 ch\u1ee9ng minh t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n th\u00f4ng d\u1ee5ng hi\u1ec7n nay.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c b\u00e0i to\u00e1n v\u1ec1 ch\u1ee9ng minh t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B\u00e0i t\u1eadp 1 (B\u00e0i 53\/SGK trang 89 To\u00e1n 9, T\u1eadp 2)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cho t\u1ee9 gi\u00e1c ABCD l\u00e0 m\u1ed9t t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m O, b\u00e1n k\u00ednh R (O;R). T\u00ednh l\u1ea7n l\u01b0\u1ee3t c\u00e1c g\u00f3c A, B, C, D c\u00f2n thi\u1ebfu (n\u1ebfu c\u00f3 th\u1ec3) trong nh\u1eefng tr\u01b0\u1eddng h\u1ee3p c\u1ee5 th\u1ec3 d\u01b0\u1edbi \u0111\u00e2y:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1eddng h\u1ee3p 1: G\u00f3c A = 80\u00ba v\u00e0 G\u00f3c B =70\u00ba<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1eddng h\u1ee3p 2: G\u00f3c C = 105\u00ba v\u00e0 G\u00f3c D =75\u00ba<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1eddng h\u1ee3p 3: G\u00f3c A = 60\u00ba<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1eddng h\u1ee3p 4: G\u00f3c B = 40\u00ba<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1eddng h\u1ee3p 5: G\u00f3c B = 65\u00ba v\u00e0 G\u00f3c C = 74\u00ba<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1eddng h\u1ee3p 6: G\u00f3c A = 95\u00ba v\u00e0 G\u00f3c D = 98\u00ba<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B\u00e0i t\u1eadp 2 (B\u00e0i 54\/SGK trang 89 To\u00e1n 9, T\u1eadp 2)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ch\u1ee9ng minh r\u1eb1ng \u0111\u01b0\u1eddng trung tr\u1ef1c AB, AC, BD \u0111\u1ec1u c\u00f9ng \u0111i qua 1 \u0111i\u1ec3m. Bi\u1ebft r\u1eb1ng t\u1ee9 gi\u00e1c ABCD c\u00f3 t\u1ed5ng c\u1ee7a g\u00f3c ABC + g\u00f3c ADC = 180\u00ba<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B\u00e0i t\u1eadp 2 (B\u00e0i 55\/SGK trang 89 To\u00e1n 9, T\u1eadp 2)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cho t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m M, ABCD bi\u1ebft r\u1eb1ng g\u00f3c DAB l\u00e0 80\u00ba, g\u00f3c DAM l\u00e0 30\u00ba, g\u00f3c BMC l\u00e0 70\u00ba. H\u00e3y t\u00ednh s\u1ed1 \u0111o c\u1ee7a nh\u1eefng g\u00f3c sau: MAB, MCD, BCM, BCD, AMB, MAD v\u00e0 DMC.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B\u00e0i gi\u1ea3ng tr\u00ean \u0111\u00e3 cung c\u1ea5p l\u00fd thuy\u1ebft, c\u00e1c c\u00e1ch ch\u1ee9ng minh v\u00e0 c\u00e1c b\u00e0i to\u00e1n v\u1ec1 ch\u1ee9ng minh t\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp th\u01b0\u1eddng g\u1eb7p hi\u1ec7n nay. Hy v\u1ecdng \u0111\u00e2y l\u00e0 nh\u1eefng ki\u1ebfn th\u1ee9c b\u1ed5 \u00edch, c\u1ea7n thi\u1ebft cho c\u00e1c b\u1ea1n <a href=\"https:\/\/www.vietlearn.org\" data-internallinksmanager029f6b8e52c=\"2\" title=\"Vietlearn\" rel=\"nofollow\">h\u1ecdc sinh<\/a>, \u0111\u1eb7c bi\u1ec7t l\u00e0 qu\u00fd ph\u1ee5 huynh. N\u1ebfu c\u00f3 nhu c\u1ea7u \u00f4n t\u1eadp nh\u1eefng ki\u1ebfn th\u1ee9c li\u00ean quan hay b\u1ea5t k\u1ef3 m\u00f4n h\u1ecdc kh\u00e1c hay th\u01b0\u1eddng xuy\u00ean c\u1eadp nh\u1eadt v\u00e0 theo d\u00f5i th\u00f4ng tin t\u1ea1i https::\/\/toppy.vn\/.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cung ch\u1ee9a g\u00f3c<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u01b0\u1eddng tr\u00f2n ngo\u1ea1i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n n\u1ed9i ti\u1ebfp<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u00ednh ch\u1ea5t c\u1ee7a hai ti\u1ebfp tuy\u1ebfn c\u1eaft nhau \u2013 H\u1ecdc h\u00ecnh l\u1edbp 9 c\u00f9ng T<\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"<p>Ghi ch\u00fa: T\u00e0i li\u1ec7u tr\u00edch d\u1eabn T\u1ee9 gi\u00e1c n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n l\u00e0 m\u1ed9t trong nh\u1eefng ch\u01b0\u01a1ng tr\u00ecnh h\u00ecnh h\u1ecdc l\u1edbp 9 v\u00f4 c\u00f9ng quan tr\u1ecdng v\u00e0 lu\u00f4n b\u1eaft g\u1eb7p trong nh\u1eefng k\u1ef3 thi. \u0110\u1ec3 hi\u1ec3u \u0111\u01b0\u1ee3c r\u00f5 h\u01a1n v\u1ec1 \u0111\u1ecbnh ngh\u0129a, c\u00e1c \u0111\u1ecbnh l\u00fd, c\u00e1ch ch\u1ee9ng minh c\u0169ng nh\u01b0 c\u00e1c b\u00e0i to\u00e1n v\u1ec1 ch\u1ee9ng [&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":[9,4],"tags":[],"class_list":["post-991","post","type-post","status-publish","format-standard","hentry","category-toan-hoc","category-trung-hoc"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/991","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=991"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/991\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=991"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=991"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=991"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}