B\u00e0i 1 (trang 121 SGK Gi\u1ea3i t\u00edch 12):\u00a0T\u00ednh di\u1ec7n t\u00edch h\u00ecnh ph\u1eb3ng gi\u1edbi h\u1ea1n b\u1edfi c\u00e1c \u0111\u01b0\u1eddng:<\/strong><\/span><\/p>\n a) y = x2<\/sup>;y = x + 2<\/strong><\/span><\/p>\n b) y =|lnx|;y = 1<\/strong><\/span><\/p>\n c) y = (x-6)2<\/sup>;y = 6x-x2<\/sup><\/strong><\/span><\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n a) Gi\u1ea3 s\u1eed \u0111\u01b0\u1eddng th\u1eb3ng y = x+2 c\u1eaft parabol y = x2<\/sup>\u00a0t\u1ea1i A v\u00e0 B.<\/p>\n xA<\/sub>, xB<\/sub>\u00a0l\u00e0 c\u00e1c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh:<\/p>\n x2<\/sup>\u00a0= x+2 \u21d4 x2<\/sup>\u00a0– x – 2 = 0<\/p>\n \u21d4 x = -1; x = 2<\/p>\n X\u00e9t h\u00e0m f(x) = x2<\/sup>\u00a0– x – 2, f\u2019(x) = 2x – 1 = 0 \u21d4 x = 1\/2<\/p>\n <\/p>\n Theo b\u1ea3ng bi\u1ebfn thi\u00ean ta c\u00f3: tr\u00ean \u0111o\u1ea1n [-1;2] th\u00ec x2<\/sup>\u00a0– x – 2 < 0<\/p>\n Do \u0111\u00f3: |x2<\/sup>\u00a0– (x + 2)|= -x2<\/sup>\u00a0+ x + 2<\/p>\n V\u1eady di\u1ec7n t\u00edch c\u1ea7n t\u00ecm l\u00e0:<\/p>\n <\/p>\n b) Ho\u00e0nh \u0111\u1ed9 c\u00e1c giao \u0111i\u1ec3m l\u00e0:<\/p>\n ln\u2061|x|=1 \u21d4x=1\/e ;x=e<\/p>\n V\u1eady di\u1ec7n t\u00edch c\u1ea7n t\u00ecm l\u00e0:<\/p>\n <\/p>\n c) Ho\u00e0nh \u0111\u1ed9 giao \u0111i\u1ec3m c\u1ee7a hai \u0111\u1ed3 th\u1ecb l\u00e0:<\/p>\n (x-6)2<\/sup>=6x-x2<\/sup><\/p>\n \u21d4 (x-6)(2x-6)=0<\/p>\n \u21d4x=3 ;x=6<\/p>\n V\u1eady di\u1ec7n t\u00edch c\u1ea7n t\u00ecm l\u00e0:<\/p>\n <\/p>\n B\u00e0i 2 (trang 121 SGK Gi\u1ea3i t\u00edch 12):\u00a0T\u00ednh di\u1ec7n t\u00edch h\u00ecnh ph\u1eb3ng gi\u1edbi h\u1ea1n b\u1edfi \u0111\u01b0\u1eddng cong y = x2<\/sup>+1 , ti\u1ebfp tuy\u1ebfn v\u1edbi \u0111\u01b0\u1eddng n\u00e0y t\u1ea1i \u0111i\u1ec3m M(2; 5) v\u00e0 tr\u1ee5c Oy.<\/strong><\/span><\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n Ph\u01b0\u01a1ng tr\u00ecnh ti\u1ebfp tuy\u1ebfn v\u1edbi \u0111\u01b0\u1eddng cong y = x2<\/sup>\u00a0+ 1 t\u1ea1i \u0111i\u1ec3m M(2; 5) l\u00e0 :<\/p>\n y‘<\/sup>=y‘<\/sup>\u00a0(2)[x – 2] + 5 \u21d4 y = 4x – 3<\/p>\n \u0110i\u1ec3m M(2; 5) thu\u1ed9c \u0111\u01b0\u1eddng y = x2<\/sup>\u00a0+ 1 v\u00ec 5 = 22<\/sup>\u00a0+ 1<\/p>\n V\u1eady di\u1ec7n t\u00edch c\u1ea7n t\u00ecm l\u00e0:<\/p>\n <\/p>\n B\u00e0i 3 (trang 121 SGK Gi\u1ea3i t\u00edch 12):\u00a0Parabol y=x2<\/sup>\/2 chia h\u00ecnh tr\u00f2n c\u00f3 t\u00e2m t\u1ea1i g\u1ed9c to\u1ea1 \u0111\u1ed9, b\u00e1n k\u00ednh 2\u221a2 th\u00e0nh hai ph\u1ea7n. T\u00ecm t\u1ec9 s\u1ed1 di\u1ec7n t\u00edch c\u1ee7a ch\u00fang.<\/strong><\/span><\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n <\/p>\n B\u00e0i 4 (trang 121 SGK Gi\u1ea3i t\u00edch 12):\u00a0T\u00ednh th\u1ec3 t\u00edch kh\u1ed1i tr\u00f2n xoay \u0111\u00f3 h\u00ecnh ph\u1eb3ng gi\u1edbi h\u1ea1n b\u1edfi c\u00e1c \u0111\u01b0\u1eddng sau quay quanh Ox:<\/strong><\/span><\/p>\n B\u00e0i 5 (trang 121 SGK Gi\u1ea3i t\u00edch 12):\u00a0Cho tam gi\u00e1c vu\u00f4ng OPM c\u00f3 c\u1ea1nh OP n\u1eb1m tr\u00ean tr\u1ee5c Ox.<\/strong><\/span><\/p>\n <\/p>\n L\u1eddi gi\u1ea3i<\/strong><\/p>\n <\/p>\n <\/p>\n<\/div>\n <\/p>\n","protected":false},"excerpt":{"rendered":" B\u00e0i 1 (trang 121 SGK Gi\u1ea3i t\u00edch 12):\u00a0T\u00ednh di\u1ec7n t\u00edch h\u00ecnh ph\u1eb3ng gi\u1edbi h\u1ea1n b\u1edfi c\u00e1c \u0111\u01b0\u1eddng: a) y = x2;y = x + 2 b) y =|lnx|;y = 1 c) y = (x-6)2;y = 6x-x2 L\u1eddi gi\u1ea3i: a) Gi\u1ea3 s\u1eed \u0111\u01b0\u1eddng th\u1eb3ng y = x+2 c\u1eaft parabol y = x2\u00a0t\u1ea1i A v\u00e0 B. xA, […]<\/p>\n","protected":false},"author":3,"featured_media":21028,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"tdm_status":"","tdm_grid_status":""},"categories":[1298],"tags":[1377,1356,1355],"yoast_head":"\n