C\u00e2u 6(1 \u0111i\u1ec3m ).<\/strong><\/p>\n Trong kh\u00f4ng gian v\u1edbi h\u1ec7 t\u1ecda \u0111\u1ed9 Oxyz<\/em> cho 3 \u0111i\u1ec3m A(1;0;0), B(0;-2;3), C(1;1;1). Ch\u1ee9ng minh A,B,C l\u00e0 3 \u0111\u1ec9nh c\u1ee7a 1 tam gi\u00e1c. T\u00ecm t\u1ecda \u0111\u1ed9 tr\u1ef1c t\u00e2m c\u1ee7a tam gi\u00e1c ABC. Vi\u1ebft ph\u01b0\u01a1ng tr\u00ecnh m\u1eb7t ph\u1eb3ng (P) ch\u1ee9a A, B sao cho kho\u1ea3ng c\u00e1ch t\u1eeb C t\u1edbi (P) l\u00e0 2\/ )<\/p>\n C\u00e2u 7(1 \u0111i\u1ec3m).<\/strong><\/p>\n Trong m\u1eb7t ph\u1eb3ng t\u1ecda \u0111\u1ed9 Oxy<\/em>, cho h\u00ecnh ch\u1eef nh\u1eadt ABCD c\u00f3 c\u00e1c c\u1ea1nh AB, AD ti\u1ebfp x\u00fac v\u1edbi \u0111\u01b0\u1eddng tr\u00f2n (C) c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh . Ph\u01b0\u01a1ng tr\u00ecnh \u0111\u01b0\u1eddng ch\u00e9o Ac: x+2y-6=0 . Ch\u1ee9ng minh \u0111\u01b0\u1eddng tr\u00f2n (C) ti\u1ebfp x\u00fac v\u1edbi tr\u1ee5c tung. G\u1ecdi N l\u00e0 ti\u1ebfp \u0111i\u1ec3m c\u1ee7a (C) v\u00e0 tr\u1ee5c tung. T\u00ecm t\u1ecda \u0111\u1ed9 c\u00e1c \u0111\u1ec9nh c\u1ee7a h\u00ecnh ch\u1eef nh\u1eadt ABCD bi\u1ebft A c\u00f3 ho\u00e0nh \u0111\u1ed9 \u00e2m v\u00e0 \u0111i\u1ec3m D c\u00f3 ho\u00e0nh \u0111\u1ed9 d\u01b0\u01a1ng, di\u1ec7n t\u00edch tam gi\u00e1c CND b\u1eb1ng 15<\/p>\n <\/p>\n <\/p>\n Xem \u0111\u1ea7y \u0111\u1ee7 \u0111\u00e1p \u00e1n t\u1ea1i \u0111\u00e2y: http:\/\/tuyensinh247.com\/khoa-98-de-thi-thu-thpt-quoc-gia-toan-hoc-hay-nhat-cua-cac-truong-thpt-chuyen-tren-toan-quoc-nam-2016-k151.html<\/strong><\/p><\/p>\n","protected":false},"excerpt":{"rendered":" \u0110\u1ec1 thi th\u1eed THPT Qu\u1ed1c gia m\u00f4n To\u00e1n n\u0103m 2016 tr\u01b0\u1eddng THPT Chuy\u00ean Th\u00e1i B\u00ecnh l\u1ea7n 3 t\u1ed5 ch\u1ee9c thi th\u1eed cho h\u1ecdc sinh kh\u1ed1i 12, c\u00f3 \u0111\u00e1p \u00e1n chi ti\u1ebft c\u00e1c em tham kh\u1ea3o d\u01b0\u1edbi \u0111\u00e2y: \u0110\u1ec1 thi th\u1eed THPT Qu\u1ed1c gia m\u00f4n To\u00e1n n\u0103m 2016 – THPT Chuy\u00ean Th\u00e1i B\u00ecnh l\u1ea7n 3 C\u00e2u […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"tdm_status":"","tdm_grid_status":""},"categories":[28],"tags":[],"yoast_head":"\n\u0110\u00e1p \u00e1n \u0111\u1ec1 thi th\u1eed THPTQG n\u0103m 2016 m\u00f4n To\u00e1n THPT Chuy\u00ean Th\u00e1i B\u00ecnh l\u1ea7n 3<\/span><\/h4>\n