C\u00e2u 6:<\/b>\u00a0GTLN c\u1ee7a h\u00e0m s\u1ed1 y = -x2<\/sup>\u00a0+ 4x + 7 \u0111\u1ea1t \u0111\u01b0\u1ee3c khi x b\u1eb1ng:<\/p>\n A. 11 \u00a0\u00a0\u00a0 B. 4<\/p>\n C. 7 \u00a0\u00a0\u00a0 D. 2<\/p>\n C\u00e2u 7:<\/b>\u00a0GTLN c\u1ee7a h\u00e0m s\u1ed1<\/p>\n <\/p>\n tr\u00ean kho\u1ea3ng (0; 4) \u0111\u1ea1t \u0111\u01b0\u1ee3c<\/p>\n A. x = 1 \u00a0\u00a0\u00a0B. x = -1 \u00a0\u00a0\u00a0 C. x = \u221a2 \u00a0\u00a0\u00a0 D. Kh\u00f4ng t\u1ed3n t\u1ea1i<\/p>\n C\u00e2u 8:<\/b>\u00a0T\u00ecm GTLN c\u1ee7a h\u00e0m s\u1ed1<\/p>\n <\/p>\n A. 0 \u00a0\u00a0\u00a0 B. +\u221e \u00a0\u00a0\u00a0 C. Kh\u00f4ng t\u1ed3n t\u1ea1i\u00a0\u00a0\u00a0 D. Kh\u00f4ng c\u00f3 \u0111\u00e1p \u00e1n<\/p>\n C\u00e2u 9:<\/b>\u00a0M\u1ed9t h\u00e0nh lang gi\u1eefa hai t\u00f2a th\u00e1p c\u00f3 h\u00ecnh d\u1ea1ng m\u1ed9t h\u00ecnh l\u0103ng tr\u1ee5 \u0111\u1ee9ng. Hai m\u1eb7t b\u00ean ABB\u2019A\u2019 v\u00e0 ACC\u2019A\u2019 l\u00e0 hai t\u1ea5m k\u00ednh h\u00ecnh ch\u1eef nh\u1eadt d\u00e0i 20m, r\u1ed9ng 5m. V\u1edbi \u0111\u1ed9 d\u00e0i x\u1ea5p x\u1ec9 n\u00e0o c\u1ee7a BC th\u00ec th\u1ec3 t\u00edch h\u00e0nh lang n\u00e0y l\u1edbn nh\u1ea5t<\/p>\n A. 6m \u00a0\u00a0\u00a0 B. 7m<\/p>\n C. 8m \u00a0\u00a0\u00a0 D. 9m.<\/p>\n <\/p>\n H\u01b0\u1edbng d\u1eabn gi\u1ea3i v\u00e0 \u0110\u00e1p \u00e1n<\/b><\/p>\n C\u00e2u 6:<\/b><\/p>\n y’ = -2x + 4 = 0 <=> x = 2<\/p>\n Ch\u1ecdn \u0111\u00e1p \u00e1n D.<\/p>\n <\/p>\n Ch\u00fa \u00fd. C\u1ea7n ph\u00e2n bi\u1ec7t GTLN c\u1ee7a h\u00e0m s\u1ed1 (max y) v\u1edbi gi\u00e1 tr\u1ecb x \u0111\u1ec3 h\u00e0m s\u1ed1 \u0111\u1ea1t \u0111\u01b0\u1ee3c GTLN.<\/p>\n C\u00e2u 7:<\/b><\/p>\n X\u00e9t<\/p>\n <\/p>\n <\/p>\n Ta c\u00f3 y’ = 0 => x = 1<\/p>\n V\u1eady h\u00e0m s\u1ed1 c\u00f3 GTLN b\u1eb1ng \u221a2 khi x = 1 . Ch\u1ecdn \u0111\u00e1p \u00e1n A.<\/p>\n C\u00e2u 8:<\/b><\/p>\n T\u1eadp x\u00e1c \u0111\u1ecbnh R.<\/p>\n <\/p>\n => v\u00f4 nghi\u1ec7m. Ta c\u00f3 b\u1ea3ng bi\u1ebfn thi\u00ean:<\/p>\n <\/p>\n H\u00e0m s\u1ed1 kh\u00f4ng c\u00f3 GTLN tr\u00ean R . Ch\u1ecdn \u0111\u00e1p \u00e1n C.<\/p>\n C\u00e2u 9:<\/b><\/p>\n Th\u1ec3 t\u00edch h\u00ecnh l\u0103ng l\u1edbn nh\u1ea5t khi v\u00e0 ch\u1ec9 khi di\u1ec7n t\u00edch \u0394ABC l\u1edbn nh\u1ea5t.<\/p>\n G\u1ecdi \u0111\u1ed9 d\u00e0i BC l\u00e0 x (m). K\u1ebb AH \u22a5 BC.<\/p>\n <\/p>\n B\u00e0i to\u00e1n \u0111\u01b0a v\u1ec1 t\u00ecm x \u2208 (0; 10)) \u0111\u1ec3 h\u00e0m s\u1ed1 y = x\u221a(100-x2<\/sup>) c\u00f3 gi\u00e1 tr\u1ecb l\u1edbn nh\u1ea5t.<\/p>\n <\/p>\n B\u1ea3ng bi\u1ebfn thi\u00ean:<\/p>\n <\/p>\n H\u00e0m s\u1ed1 \u0111\u1ea1t gi\u00e1 tr\u1ecb l\u1edbn nh\u1ea5t t\u1ea1i x = 5\u221a2 \u2248 7. Ch\u1ecdn \u0111\u00e1p \u00e1n B.<\/p>\n","protected":false},"excerpt":{"rendered":" C\u00e2u 6:\u00a0GTLN c\u1ee7a h\u00e0m s\u1ed1 y = -x2\u00a0+ 4x + 7 \u0111\u1ea1t \u0111\u01b0\u1ee3c khi x b\u1eb1ng: A. 11 \u00a0\u00a0\u00a0 B. 4 C. 7 \u00a0\u00a0\u00a0 D. 2 C\u00e2u 7:\u00a0GTLN c\u1ee7a h\u00e0m s\u1ed1 tr\u00ean kho\u1ea3ng (0; 4) \u0111\u1ea1t \u0111\u01b0\u1ee3c A. x = 1 \u00a0\u00a0\u00a0B. x = -1 \u00a0\u00a0\u00a0 C. x = \u221a2 \u00a0\u00a0\u00a0 D. Kh\u00f4ng t\u1ed3n t\u1ea1i […]<\/p>\n","protected":false},"author":3,"featured_media":27989,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"tdm_status":"","tdm_grid_status":""},"categories":[157],"tags":[1447,1446],"yoast_head":"\n\n\n
\n 6-D<\/td>\n 7-A<\/td>\n 8-C<\/td>\n 9-B<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n