B\u00e0i 27 (trang 205 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao)<\/b><\/span><\/p>\n H\u00e3y t\u00ecm d\u1ea1ng l\u01b0\u1ee3ng gi\u00e1c c\u1ee7a c\u00e1c s\u1ed1 ph\u1ee9c:\u00a0z\u2212<\/i>; -z;1\/z;kz (k \u2208R^*) trong m\u1ed7i tr\u01b0\u1eddng h\u1ee3p sau:<\/p>\n a) z=r(cos\u2061\u03c6+isin \u03c6)(r>0)<\/p>\n b) z=1+i \u221a3<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n a) Ta c\u00f3:\u00a0z\u2212<\/i>=r(cos\u2061\u03c6-isin \u03c6)<\/p>\n -z=-r(cos\u2061\u03c6+isin \u03c6)=r(cos\u2061(\u03c6+\u03c0)+isin (\u03c6+\u03c0)<\/p>\n <\/p>\n Kz l\u00e0 m\u1ed9t s\u1ed1 ph\u1ee9c c\u00f3 modun l\u00e0 |Kz| = |K|. |z| = |K|.r, c\u00f3 acgumen l\u00e0 \u03c6 n\u1ebfu K > 0, l\u00e0 \u03c6+\u03c0 n\u1ebfu k < 0.<\/p>\n V\u1eady Kz = |K|.r(cos\u2061\u03c6+isin \u03c6) n\u1ebfu k > 0<\/p>\n KZ = |K|r. (cos\u2061(\u03c6+\u03c0)+isin (\u03c6+\u03c0) n\u1ebfu k > 0<\/p>\n <\/p>\n B\u00e0i 28 (trang 205 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao)<\/b><\/span><\/p>\n Vi\u1ebft Ph\u01b0\u01a1ng tr\u00ecnh sau d\u01b0\u1edbi d\u1ea1ng l\u01b0\u1ee3ng gi\u00e1c.<\/p>\n a) 1-i \u221a3; 1+i; (1-i \u221a3)(1+i);(1-\u221a3 i)\/(1+i )<\/p>\n b) 2i(\u221a3-i)<\/p>\n c) 1\/(2+2i)<\/p>\n d) z=sin\u2061\u03b1+cos\u2061\u03b1 (\u03b1 \u2208R)<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n <\/p>\n <\/p>\n<\/div>\n B\u00e0i 29 (trang 206 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):<\/b><\/span><\/p>\n D\u00f9ng c\u00f4ng th\u1ee9c khai tri\u1ec3n nh\u1ecb th\u1ee9c Niut\u01a1n (1+i)19<\/sup>\u00a0v\u00e0 c\u00f4ng th\u1ee9c Moa-vr\u01a1 \u0111\u1ec3 t\u00ednh:<\/p>\n <\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n Theo nh\u1ecb th\u1ee9c Nui t\u01a1n ta c\u00f3:<\/p>\n <\/p>\n N\u00ean c\u00f4ng th\u1ee9c Moa- vr\u01a1 ta c\u00f3:<\/p>\n <\/p>\n So s\u00e1nh (1) v\u00e0 (2) ta c\u00f3:<\/p>\n <\/p>\n<\/div>\n B\u00e0i 30 (trang 206 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao)<\/b><\/span><\/p>\n G\u1ecdi M, M\u2019 l\u00e0 c\u00e1c \u0111i\u1ec3m trong m\u1eb7t ph\u1eb3ng ph\u1ee9c theo th\u1ee9 t\u1ef1 bi\u1ec3u di\u1ec5n c\u00e1c s\u1ed1 z=3+i;z’=(3-\u221a3)+(1+3\u221a3)i<\/p>\n a) T\u00ednh z’\/z<\/p>\n b) Ch\u1ee9ng minh r\u1eb1ng hi\u1ec7u s\u1ed1 acgumen c\u1ee7a z\u2019 v\u1edbi acguemn c\u1ee7a z l\u00e0 m\u1ed9t s\u1ed1 \u0111o c\u1ee7a g\u00f3c l\u01b0\u1ee3ng gi\u00e1c (OM, OM\u2019). T\u00ednh s\u1ed1 \u0111o \u0111\u00f3.<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n <\/p>\n T\u1eeb (1) v\u00e0 (2) ta c\u00f3: cos\u2061(\u03b1’-\u03b1)=cos\u2061(OM,OM’) n\u00ean k\u00ed hi\u1ec7u \u03b1’-\u03b1 l\u00e0 m\u1ed9t s\u1ed1 \u0111o c\u1ee7a g\u00f3c l\u01b0\u1ee3ng gi\u00e1c (OM, OM\u2019) v\u00e0 s\u1ed1 \u0111o l\u00e0<\/p>\n <\/p>\n<\/div>\n B\u00e0i 31 (trang 206 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao):<\/b><\/span><\/p>\n Cho c\u00e1c s\u1ed1 ph\u1ee9c<\/p>\n <\/p>\n a) Ch\u1ee9ng minh r\u1eb1ng<\/p>\n <\/p>\n l\u00e0 c\u00e1c nghi\u1ec7m c\u1ee7a Ph\u01b0\u01a1ng tr\u00ecnh z3<\/sup>-w=0<\/p>\n b) Bi\u1ec3u th\u1ee9c s\u1ed1 h\u1ecdc c\u00e1c s\u1ed1 ph\u1ee9c z0<\/sub>;z1<\/sub>;z2<\/sub><\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n <\/p>\n V\u1eady z0<\/sub>3<\/sup>-w=0 hay z0<\/sub>\u00a0l\u00e0 m\u1ed9t nghi\u1ec7m c\u1ee7a Ph\u01b0\u01a1ng tr\u00ecnh: z3<\/sup>-w=0<\/p>\n <\/p>\n V\u1eady z2<\/sub>\u00a0c\u0169ng l\u00e0 m\u1ed9t nghi\u1ec7m c\u1ee7a Ph\u01b0\u01a1ng tr\u00ecnh z3<\/sup>-w=0<\/p>\n b) C\u00e1c \u0111i\u1ec3m A, B, C l\u1ea7n l\u01b0\u1ee3t bi\u1ec3u di\u1ec5n c\u00e1c s\u1ed1:<\/p>\n <\/p>\n <\/p>\n nh\u1eadn x\u00e9t: ba \u0111i\u1ec3m A, B, C t\u1ea1o th\u00e0nh m\u1ed9t tam gi\u00e1c \u0111\u1ec1u.<\/p>\n B\u00e0i 27 (trang 205 sgk Gi\u1ea3i T\u00edch 12 n\u00e2ng cao) H\u00e3y t\u00ecm d\u1ea1ng l\u01b0\u1ee3ng gi\u00e1c c\u1ee7a c\u00e1c s\u1ed1 ph\u1ee9c:\u00a0z\u2212; -z;1\/z;kz (k \u2208R^*) trong m\u1ed7i tr\u01b0\u1eddng h\u1ee3p sau: a) z=r(cos\u2061\u03c6+isin \u03c6)(r>0) b) z=1+i \u221a3 L\u1eddi gi\u1ea3i: a) Ta c\u00f3:\u00a0z\u2212=r(cos\u2061\u03c6-isin \u03c6) -z=-r(cos\u2061\u03c6+isin \u03c6)=r(cos\u2061(\u03c6+\u03c0)+isin (\u03c6+\u03c0) Kz l\u00e0 m\u1ed9t s\u1ed1 ph\u1ee9c c\u00f3 modun l\u00e0 |Kz| = |K|. |z| = […]<\/p>\n","protected":false},"author":3,"featured_media":22803,"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