![\"cach-giai-quyet-3-cau-hoi-kho-hoc-bua-trong-de-thi-THPT-Quoc-Gia-mon-To\u00e1n\"](\"https:\/\/onthitot.com\/wp-content\/uploads\/2016\/04\/cach-giai-quyet-3-cau-hoi-kho-hoc-bua-trong-de-thi-THPT-Quoc-Gia-mon-To\u00e1n.jpg\")
<\/a>Th\u1ea7y L\u00ea Anh Tu\u1ea5n, gi\u1ea3ng vi\u00ean \u0110\u1ea1i h\u1ecdc C\u00f4ng nghi\u1ec7p H\u00e0 N\u1ed9i chia s\u1ebb<\/em><\/p>\nH\u1ecdc sinh n\u1ebfu c\u00f3 m\u1ee5c ti\u00eau \u0111\u1ea1t \u0111i\u1ec3m 8 tr\u1edf l\u00ean c\u1ea7n b\u1ed1 tr\u00ed th\u1eddi gian \u00f4n t\u1eadp th\u1eadt chi ti\u1ebft. N\u00ean d\u00e0nh kho\u1ea3ng 2 tu\u1ea7n l\u1ec5 \u0111\u1ec3 h\u1ecdc v\u00e0 t\u1ed5ng h\u1ee3p t\u1ea5t c\u1ea3 k\u1ef9 n\u0103ng l\u00e0m b\u00e0i c\u0169ng nh\u01b0 l\u00fd thuy\u1ebft c\u1ea7n nh\u1edb, b\u00e1m s\u00e1t ki\u1ebfn th\u1ee9c s\u00e1ch gi\u00e1o khoa c\u1ee7a c\u00e1c d\u1ea1ng To\u00e1n c\u01a1 b\u1ea3n \u0111\u1ec3 \u0111\u1ea1t t\u1eeb 1 \u0111\u1ebfn 7 \u0111i\u1ec3m nh\u01b0: Kh\u1ea3o s\u00e1t h\u00e0m s\u1ed1 v\u00e0 b\u00e0i to\u00e1n li\u00ean quan, L\u01b0\u1ee3ng gi\u00e1c, M\u0169 v\u00e0 logarit, S\u1ed1 ph\u1ee9c, T\u00edch ph\u00e2n, H\u00ecnh gi\u1ea3i t\u00edch kh\u00f4ng gian Oxyz, X\u00e1c su\u1ea5t v\u00e0 Nh\u1ecb th\u1ee9c niu t\u01a1n, H\u00ecnh h\u1ecdc kh\u00f4ng gian. \u0110\u1ea3m b\u1ea3o r\u1eb1ng c\u00e1c em ph\u1ea3i ki\u1ebfm tr\u1ecdn v\u1eb9n 7 \u0111i\u1ec3m n\u00e0y. Th\u1eddi gian c\u00f2n l\u1ea1i h\u00e3y h\u1ecdc song song 2 ch\u1ee7 \u0111\u1ec1 l\u1ea5y 8 v\u00e0 9 \u0111i\u1ec3m.<\/p>\n
C\u00e2u \u0111i\u1ec3m 8:<\/strong> Th\u01b0\u1eddng l\u00e0 c\u00e2u v\u1ec1 t\u1ecda \u0111\u1ed9 ph\u1eb3ng Oxy. Xu h\u01b0\u1edbng ra \u0111\u1ec1 g\u1ea7n \u0111\u00e2y l\u00e0 t\u1eeb h\u00ecnh v\u1ebd ph\u00e1t hi\u1ec7n ra m\u1ed9t t\u00ednh ch\u1ea5t \u0111\u1eb7c bi\u1ec7t nh\u01b0 quan h\u1ec7 vu\u00f4ng g\u00f3c, song song\u2026 r\u1ed3i ch\u1ee9ng minh t\u00ednh ch\u1ea5t n\u00e0y. Mu\u1ed1n h\u1ecdc ph\u1ea7n n\u00e0y d\u1ec5 d\u00e0ng, c\u00e1c em c\u1ea7n h\u1ecdc \u0111\u01b0\u1ee3c c\u00e1ch khai tri\u1ec3n b\u00e0i to\u00e1n, ch\u1ee9 kh\u00f4ng ph\u1ea3i h\u1ecdc thu\u1ed9c t\u00ednh ch\u1ea5t c\u00f3 s\u1eb5n c\u1ee7a h\u00ecnh v\u1ebd, nh\u01b0 v\u1eady s\u1ebd b\u1ecb \u0111\u1ed9ng v\u00e0 hoang mang. G\u1eb7p m\u1ed7i b\u00e0i to\u00e1n m\u1edbi, c\u00e1c em s\u1ebd nh\u01b0 ch\u00e0ng t\u00ed hon m\u00e0 g\u1eb7p m\u1ed9t c\u01a1n b\u00e3o l\u1edbn. V\u00ec v\u1eady, c\u1ea7n bi\u1ebft c\u00e1ch khai tri\u1ec3n b\u00e0i to\u00e1n b\u1ea5t k\u1ef3, v\u00ed d\u1ee5:<\/p>\n – N\u1ebfu y\u00eau c\u1ea7u t\u00ecm \u0111i\u1ec3m M m\u00e0 cho bi\u1ebft t\u1ecda \u0111\u1ed9 m\u1ed9t \u0111i\u1ec3m E th\u00ec ngh\u0129 t\u1edbi vi\u1ec7c t\u00ednh kho\u1ea3ng c\u00e1ch ME.<\/p>\n – N\u1ebfu y\u00eau c\u1ea7u t\u00ecm \u0111i\u1ec3m M m\u00e0 cho bi\u1ebft t\u1ecda \u0111\u1ed9 hai \u0111i\u1ec3m E, F th\u00ec ngh\u0129 t\u1edbi vi\u1ec7c ph\u00e1t hi\u1ec7n tam gi\u00e1c MEF vu\u00f4ng, c\u00e2n hay \u0111\u1ec1u\u2026<\/p>\n C\u00f2n vi\u1ec7c ch\u1ee9ng minh c\u0169ng c\u1ea7n h\u1ecdc k\u1ef9 thu\u1eadt khai tri\u1ec3n. C\u00f3 nh\u01b0 v\u1eady c\u00e1c em m\u1edbi th\u1ea5y c\u00e2u Oxy th\u1eadt nh\u1eb9 nh\u00e0ng, v\u00e0 ch\u1ec9 c\u1ea7n 2 tu\u1ea7n h\u1ecdc l\u00e0 h\u1ecdc sinh c\u00f3 th\u1ec3 t\u1ef1 tin v\u1ec1 c\u00e2u n\u00e0y.<\/p>\n C\u00e2u \u0111i\u1ec3m 9:<\/strong> Th\u01b0\u1eddng l\u00e0 c\u00e2u v\u1ec1 ph\u01b0\u01a1ng tr\u00ecnh, b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh, h\u1ec7 ph\u01b0\u01a1ng tr\u00ecnh. \u0110\u1ec3 l\u00e0m \u0111\u01b0\u1ee3c c\u00e2u n\u00e0y, h\u1ecdc sinh c\u1ea7n h\u1ecdc b\u00e0i b\u1ea3n c\u00e1c k\u1ef9 thu\u1eadt gi\u1ea3i ch\u00ednh nh\u01b0 li\u00ean h\u1ee3p, \u0111\u1eb7t nh\u00e2n t\u1eed chung, h\u00e0m \u0111\u1eb7c tr\u01b0ng, \u0111\u1eb7t \u1ea9n ph\u1ee5, \u0111\u00e1nh gi\u00e1… \u0110\u00e2y l\u00e0 c\u00e2u v\u1eadn d\u1ee5ng m\u1ee9c \u0111\u1ed9 cao nh\u01b0ng kh\u00f4ng ph\u1ea3i l\u00e0 qu\u00e1 kh\u00f3, c\u1ea7n n\u1eafm v\u1eefng k\u1ef9 thu\u1eadt v\u00e0 l\u00e0m nhi\u1ec1u b\u00e0i t\u1eadp t\u1ef1 luy\u1ec7n \u0111\u1ec3 h\u00ecnh th\u00e0nh ph\u1ea3n x\u1ea1 th\u00ec vi\u1ec7c ki\u1ebfm \u0111\u01b0\u1ee3c 0,75 \u0111i\u1ec3m-1 \u0111i\u1ec3m c\u1ee7a c\u00e2u n\u00e0y l\u00e0 trong t\u1ea7m tay.<\/p>\n C\u00e2u \u0111i\u1ec3m 10:<\/strong> Th\u01b0\u1eddng l\u00e0 c\u00e2u thu\u1ed9c ch\u1ee7 \u0111\u1ec1 b\u1ea5t \u0111\u1eb3ng th\u1ee9c, gi\u00e1 tr\u1ecb l\u1edbn nh\u1ea5t, gi\u00e1 tr\u1ecb nh\u1ecf nh\u1ea5t. C\u00e2u n\u00e0y d\u00e0nh cho c\u00e1c em \u0111\u00e3 c\u00f3 c\u1ea3 m\u1ed9t qu\u00e1 tr\u00ecnh \u00f4n luy\u1ec7n r\u1ea5t d\u00e0i, v\u00e0 ph\u1ea3i c\u00f3 t\u01b0 duy r\u1ea5t t\u1ed1t. \u0110\u1ec3 l\u00e0m \u0111\u01b0\u1ee3c c\u00e2u n\u00e0y c\u1ea7n n\u1eafm v\u1eefng k\u1ef9 thu\u1eadt ch\u1ecdn \u0111i\u1ec3m r\u01a1i; c\u00e1c b\u1ea5t \u0111\u1eb3ng th\u1ee9c ph\u1ee5 c\u01a1 b\u1ea3n v\u00e0 \u00fd t\u01b0\u1edfng khai tri\u1ec3n b\u00e0i to\u00e1n.<\/p>\n Tuy nhi\u00ean, n\u1ebfu trong qu\u00e1 tr\u00ecnh \u00f4n t\u1eadp m\u00e0 lu\u00f4n g\u1eb7p kh\u00f3 kh\u0103n v\u1edbi c\u00e2u h\u1ecfi \u201cv\u00e0ng m\u01b0\u1eddi\u201d n\u00e0y th\u00ec h\u1ecdc sinh n\u00ean b\u1ecf qua, \u0111\u1ec3 d\u00e0nh th\u1eddi gian \u0111\u1ec3 ki\u1ebfm tr\u1ecdn 9 \u0111i\u1ec3m nh\u1eefng c\u00e2u tr\u01b0\u1edbc, v\u00ec 9 \u0111i\u1ec3m \u0111\u00e3 l\u00e0 th\u00e0nh c\u00f4ng r\u1ed3i.<\/p>\n Th\u1eddi gian kh\u00f4ng c\u00f2n qu\u00e1 nhi\u1ec1u \u0111\u1ec3 h\u1ecdc lan man, h\u00e3y ph\u00e2n b\u1ed5 th\u1eddi gian h\u1ee3p l\u00fd, l\u1ef1a ch\u1ecdn ki\u1ebfn th\u1ee9c ph\u00f9 h\u1ee3p v\u1edbi n\u0103ng l\u1ef1c c\u1ee7a m\u00ecnh \u0111\u1ec1 c\u00f3 th\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c \u0111i\u1ec3m s\u1ed1 cao trong k\u1ef3 thi.<\/p>\n M\u1eddi c\u00e1c b\u1ea1n xem th\u00eam tuy\u1ec3n t\u1eadp b\u1ed9 3 c\u00e2u h\u1ecfi kh\u00f3 ph\u00e2n lo\u1ea1i trong \u0111\u1ec1 thi th\u1eed THPT Qu\u1ed1c gia m\u00f4n To\u00e1n\u200b n\u0103m 2015 v\u1ec1 ph\u01b0\u01a1ng tr\u00ecnh, h\u1ec7 ph\u01b0\u01a1ng tr\u00ecnh, b\u1ea5t ph\u01b0\u01a1ng tr\u00ecnh, ph\u01b0\u01a1ng ph\u00e1p t\u1ecda \u0111\u1ed9 trong m\u1eb7t ph\u1eb3ng, b\u1ea5t \u0111\u1eb3ng th\u1ee9c, t\u00ecm gi\u00e1 tr\u1ecb l\u1edbn nh\u1ea5t v\u00e0 gi\u00e1 tr\u1ecb nh\u1ecf nh\u1ea5t.<\/p>\n