B\u00e0i 59 (trang 117 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):<\/b>\u00a0<\/span><\/p>\n T\u00ednh gi\u00e1 tr\u1ecb g\u1ea7n \u0111\u00fang c\u1ee7a \u0111\u1ea1o h\u00e0m c\u1ee7a m\u1ed7i h\u00e0m s\u1ed1 sau t\u1ea1i \u0111i\u1ec3m \u0111\u00e3 cho (ch\u00ednh x\u00e1c \u0111\u1ebfn h\u00e0ng ph\u1ea7n tr\u0103m)<\/p>\n <\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n <\/p>\n B\u00e0i 60 (trang 117 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):<\/b><\/span><\/p>\n a) Ch\u1ee9ng minh r\u1eb1ng \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1 y=ax<\/sup>\u00a0v\u00e0 y=(1\/a)x<\/sup>\u00a0\u0111\u1ed1i x\u1ee9ng v\u1edbi nhau qua tr\u1ee5c tung.<\/p>\n b) Ch\u1ee9ng minh r\u1eb1ng \u0111\u1ed3 th\u1ecb c\u1ee7a hai h\u00e0m s\u1ed1 y=loga<\/sub>\u2061x v\u00e0 y=log1\/a<\/sub>\u2061x \u0111\u1ed1i x\u1ee9ng nhau qua tr\u1ee5c ho\u00e0nh.<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n a) G\u1ecdi (C1<\/sub>) v\u00e0 (C2<\/sub>) l\u1ea7n l\u01b0\u1ee3t l\u00e0 \u0111\u1ed3 th\u1ecb c\u1ee7a c\u00e1c h\u00e0m s\u1ed1<\/p>\n <\/p>\n M(x0<\/sub>,y0<\/sub>\u00a0) l\u00e0 m\u1ed9t \u0111i\u1ec3m b\u1ea5t k\u00ec. Khi \u0111\u00f3 \u0111i\u1ec3m \u0111\u1ed1i x\u1ee9ng v\u1edbi M qua tr\u1ee5c tung l\u00e0 M'(-x0<\/sub>;y0<\/sub>)<\/p>\n Ta c\u00f3: M \u2208(C1<\/sub>\u00a0) <=> y0<\/sub>=ax0<\/sub><\/sup><\/p>\n <\/p>\n \u0110i\u1ec1u \u0111\u00f3 ch\u1ee9ng t\u1ecf (C1<\/sub>) v\u00e0 (C2<\/sub>\u00a0)\u0111\u1ed1i x\u1ee9ng nhau qua tr\u1ee5c tung.<\/p>\n b) Ch\u1ee9ng minh t\u01b0\u01a1ng \u0111\u01b0\u01a1ng b\u00e0i a, ch\u00fa \u00fd \u0111i\u1ec3m \u0111\u1ed1i x\u1ee9ng v\u1edbi M(x0<\/sub>;y0<\/sub>\u00a0) qua tr\u1ee5c ho\u00e0nh l\u00e0 \u0111i\u1ec3m M'(x0<\/sub>; -y0<\/sub>)<\/p>\n M \u2208(C1<\/sub>\u00a0)<=> y0<\/sub>=loga<\/sub>\u2061x0<\/sub>\u00a0<=> y0<\/sub>=-log1\/a<\/sup>\u2061x0<\/sub>\u00a0<=> -y0<\/sub>=log1\/a<\/sub>\u2061x0<\/sub>\u00a0<=> M’\u2208(C2<\/sub>)<\/p>\n B\u00e0i 61 (trang 118 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):<\/b>\u00a0<\/span><\/p>\n V\u1ebd \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1 y=log0,5<\/sub>\u2061x. d\u1ef1a v\u00e0o \u0111\u1ed3 th\u1ecb h\u00e3y gi\u1ea3i c\u00e1c b\u1ea5t Ph\u01b0\u01a1ng tr\u00ecnh sau:<\/p>\n a) log0,5<\/sub>\u2061x > 0 \u00a0\u00a0\u00a0 b) -3 \u2264 log0,5<\/sub>\u2061x < -1<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n \u0110\u1ed3 th\u1ecb h\u00e0m s\u1ed1 l\u00e0 h\u00ecnh v\u1ebd b\u00ean.<\/p>\n <\/p>\n a) log0,5<\/sub>\u2061x > 0 l\u00e0 nh\u1eefng \u0111i\u1ec3m n\u1eb1m \u1edf ph\u00eda tr\u00ean tr\u1ee5c ho\u00e0nh.<\/p>\n log0,5<\/sub>\u2061x > 0 <=> 0 < x < 1<\/p>\n b) -3 \u2264 log0,5<\/sub>x < -1 ( y=log0,5<\/sub>\u2061x l\u00e0 nh\u1eefng \u0111i\u1ec3m tr\u00ean \u0111\u1ed3 th\u1ecb c\u00f3 tung \u0111\u1ed9 thu\u1ed9c n\u1eeda kho\u1ea3ng [-3; 1))<\/p>\n -3 \u2264 log0,5<\/sub>\u2061x < -1 <=> 2 < x\u22648<\/p>\n B\u00e0i 62 (trang 118 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):<\/b>\u00a0<\/span><\/p>\n V\u1ebd \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1 y=(\u221a3)x<\/sub>. d\u1ef1a v\u00e0o \u0111\u1ed3 th\u1ecb, h\u00e3y gi\u1ea3i c\u00e1c b\u1ea5t Ph\u01b0\u01a1ng tr\u00ecnh sau:<\/p>\n a) (\u221a3)x<\/sup>\u00a0\u2264 1 \u00a0\u00a0\u00a0\u00a0 b) (\u221a3)x<\/sup>\u00a0< 3<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n \u0110\u1ed3 th\u1ecb h\u00e0m s\u1ed1 y=(\u221a3)x<\/sup>\u00a0c\u00f3 h\u00ecnh v\u1ebd b\u00ean.<\/p>\n <\/p>\n a) (\u221a3)x<\/sup>\u00a0< 1 (tung \u0111\u1ed9 y=(\u221a3)x<\/sup>\u00a0kh\u00f4ng l\u1edbn h\u01a1n 1)<\/p>\n => (\u221a3)x<\/sup>\u00a0\u2264 1 <=> x \u2264 0<\/p>\n b) (\u221a3)x<\/sup>\u00a0> 3 (tung \u0111\u1ed9 y=(\u221a3)x<\/sup>\u00a0l\u1edbn h\u01a1n 3)<\/p>\n => (\u221a3)x<\/sup>\u00a0> 3 <=> x > 2<\/p>\n B\u00e0i 59 (trang 117 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):\u00a0 T\u00ednh gi\u00e1 tr\u1ecb g\u1ea7n \u0111\u00fang c\u1ee7a \u0111\u1ea1o h\u00e0m c\u1ee7a m\u1ed7i h\u00e0m s\u1ed1 sau t\u1ea1i \u0111i\u1ec3m \u0111\u00e3 cho (ch\u00ednh x\u00e1c \u0111\u1ebfn h\u00e0ng ph\u1ea7n tr\u0103m) L\u1eddi gi\u1ea3i: B\u00e0i 60 (trang 117 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao): a) Ch\u1ee9ng minh r\u1eb1ng \u0111\u1ed3 th\u1ecb h\u00e0m s\u1ed1 y=ax\u00a0v\u00e0 y=(1\/a)x\u00a0\u0111\u1ed1i […]<\/p>\n","protected":false},"author":3,"featured_media":23458,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"tdm_status":"","tdm_grid_status":""},"categories":[1302],"tags":[1392,1393],"yoast_head":"\n