\u00a0L\u1eddi gi\u1ea3i:<\/b><\/p>\n

a) M\u1ed7i s\u1ed1 ph\u1ee9c z = a + bi c\u00f3 \u0111i\u1ec3m bi\u1ec3u di\u1ec5n trong mi\u1ec1n g\u1ea1ch s\u1ecdc \u1edf h\u00ecnh a ph\u1ea3i th\u1ecfa m\u00e3n \u0111i\u1ec1u ki\u1ec7n: ph\u1ea7n th\u1ef1c a \u22651 ( ph\u1ea7n \u1ea3o b b\u1ea5t k\u00ec).<\/p>\n

b) S\u1ed1 ph\u1ee9c z = a + bi c\u00f3 \u0111i\u1ec3m bi\u1ec3u di\u1ec5n trong mi\u1ec1n g\u1ea1ch s\u1ecdc \u1edf h\u00ecnh b ph\u1ea3i th\u1ecfa m\u00e3n \u0111i\u1ec1u ki\u1ec7n : ph\u1ea7n \u1ea3o b \u2208[-1;2] ( ph\u1ea7n th\u1ef1c a b\u1ea5t k\u00ec).<\/p>\n

c) \u0110i\u1ec1u ki\u1ec7n: m\u00f4 \u0111un \u2264 2 , ph\u1ea7n th\u1ef1c a \u2208 [-1;1]<\/p>\n

B\u00e0i 2 (trang 143 SGK Gi\u1ea3i t\u00edch 12):\u00a0Th\u1ebf n\u00e0o l\u00e0 ph\u1ea7n th\u1ef1c ph\u1ea7n \u1ea3o, m\u00f4 \u0111un c\u1ee7a m\u1ed9t s\u1ed1 ph\u1ee9c? Vi\u1ebft c\u00f4ng th\u1ee9c t\u00ednh m\u00f4 \u0111un c\u1ee7a s\u1ed1 ph\u1ee9c theo ph\u1ea7n th\u1ef1c ph\u1ea7n \u1ea3o c\u1ee7a n\u00f3?<\/strong><\/span><\/p>\n

L\u1eddi gi\u1ea3i:<\/b><\/p>\n

M\u1ed7i s\u1ed1 ph\u1ee9c l\u00e0 m\u1ed9t bi\u1ec3u th\u1ee9c z = a + bi v\u1edbi a,b \u2208 R,i^{2<\/sup>\u00a0= -1<\/p>\n}

– S\u1ed1 th\u1ef1c a l\u00e0 ph\u1ea7n th\u1ef1c c\u1ee7a s\u1ed1 ph\u1ee9c: z = a + bi<\/p>\n

– S\u1ed1 th\u1ef1c b l\u00e0 ph\u1ea7n \u1ea3o c\u1ee7a s\u1ed1 ph\u1ee9c z = a + bi<\/p>\n

– \u0110i\u1ec3m M(a; b) tr\u00ean m\u1eb7t ph\u1eb3ng t\u1ecda \u0111\u1ed9 bi\u1ec3u di\u1ec5n s\u1ed1 ph\u1ee9c z = a + bi<\/p>\n

<\/p>\n

B\u00e0i 3 (trang 143 SGK Gi\u1ea3i t\u00edch 12):\u00a0T\u00ecm m\u1ed1i li\u00ean h\u1ec7 gi\u1eefa kh\u00e1i ni\u00eam m\u00f4 \u0111un v\u00e0 kh\u00e1i ni\u1ec7m gi\u00e1 tr\u1ecb tuy\u1ec7t \u0111\u1ed1i c\u1ee7a s\u1ed1 th\u1ef1c.<\/strong><\/span><\/p>\n

L\u1eddi gi\u1ea3i:<\/b><\/p>\n

M\u1ed7i s\u1ed1 th\u1ef1c a \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 s\u1ed1 ph\u1ee9c c\u00f3 ph\u1ea7n \u1ea3o b\u1eb1ng 0<\/p>\n

Ta c\u00f3: a \u2208 R => a = a + 0i<\/p>\n

M\u00f4 \u0111un c\u1ee7a s\u1ed1 th\u1ef1c a l\u00e0:<\/p>\n

<\/p>\n

 <\/p>\n

Nh\u01b0 v\u1eady v\u1edbi m\u1ed9t s\u1ed1 th\u1ef1c, kh\u00e1i ni\u1ec7m m\u00f4 \u0111un v\u00e0 kh\u00e1i ni\u1ec7m gi\u00e1 tr\u1ecb tuy\u1ec7t \u0111\u1ed1i l\u00e0 \u0111\u1ed3ng nh\u1ea5t.<\/p>\n

B\u00e0i 4 (trang 143 SGK Gi\u1ea3i t\u00edch 12):\u00a0N\u00eau \u0111\u1ecbnh ngh\u0129a s\u1ed1 ph\u1ee9c li\u00ean h\u1ee3p v\u1edbi s\u1ed1 ph\u1ee9c z. S\u1ed1 ph\u1ee9c n\u00e0o b\u1eb1ng s\u1ed1 ph\u1ee9c li\u00ean h\u1ee3p c\u1ee7a n\u00f3?<\/strong><\/span><\/p>\n

L\u1eddi gi\u1ea3i:<\/b><\/p>\n

<\/p>\n

B\u00e0i 5 (trang 143 SGK Gi\u1ea3i t\u00edch 12):\u00a0Tr\u00ean m\u1eb7t ph\u1eb3ng t\u1ecda \u0111\u1ed9, t\u00ecm t\u1eadp h\u1ee3p bi\u1ec3u di\u1ec5n c\u1ee7a c\u00e1c s\u1ed1 ph\u1ee9c z th\u1ecfa m\u00e3n \u0111i\u1ec1u ki\u1ec7n:<\/strong><\/span><\/p>\n

a) Ph\u1ea7n th\u1ef1c c\u1ee7a z b\u1eb1ng 1<\/strong><\/span><\/p>\n

b) Ph\u1ea7n \u1ea3o c\u1ee7a z b\u1eb1ng -2<\/strong><\/span><\/p>\n

c) Ph\u1ea7n th\u1ef1c c\u1ee7a z thu\u1ed9c \u0111o\u1ea1n [-1; 2], ph\u1ea7n \u1ea3o c\u1ee7a z thu\u1ed9c \u0111o\u1ea1n [0; 1]<\/strong><\/span><\/p>\n

d) |z|\u22642<\/strong><\/span><\/p>\n

 <\/p>\n

L\u1eddi gi\u1ea3i:<\/b><\/p>\n

a) T\u1eadp h\u1ee3p c\u00e1c \u0111i\u1ec3m thu\u1ed9c \u0111\u01b0\u1eddng th\u1eb3ng x =1<\/p>\n

b) T\u1eadp h\u1ee3p c\u00e1c \u0111i\u1ec3m thu\u1ed9c \u0111\u01b0\u1eddng th\u1eb3ng y= -2<\/p>\n

c) T\u1eadp h\u1ee3p c\u00e1c \u0111i\u1ec3m thu\u1ed9c h\u00ecnh ch\u1eef nh\u1eadt c\u00f3 c\u00e1c c\u1ea1nh n\u1eb1m tr\u00ean c\u00e1c \u0111\u01b0\u1eddng th\u1eb3ng x= -1, x= 2, y= 0, y= 1 (h\u00ecnh g\u1ea1ch s\u1ecdc).<\/p>\n

d) T\u1eadp h\u1ee3p c\u00e1c \u0111i\u1ec3m thu\u1ed9c h\u00ecnh tr\u00f2n t\u00e2m O(0,0), b\u00e1n k\u00ednh b\u1eb1ng 2.<\/p>\n

B\u00e0i 6 (trang 143 SGK Gi\u1ea3i t\u00edch 12):\u00a0T\u00ecm c\u00e1c s\u1ed1 th\u1ef1c x, y sao cho:<\/strong><\/span><\/p>\n

a) 3x+yi=2y+1+(2-x)i<\/strong><\/span><\/p>\n

b) 2x+y-1=(x+2y-5)i<\/strong><\/span><\/p>\n

L\u1eddi gi\u1ea3i:<\/b><\/p>\n

<\/p>\n

B\u00e0i 7 (trang 143 SGK Gi\u1ea3i t\u00edch 12):\u00a0Ch\u1ee9ng t\u1ecf r\u1eb1ng v\u1edbi m\u1ecdi s\u1ed1 th\u1ef1c z, ta lu\u00f4n ph\u1ea7n th\u1ef1c v\u00e0 ph\u1ea7n \u1ea3o c\u1ee7a n\u00f3 kh\u00f4ng v\u01b0\u1ee3t qu\u00e1 m\u00f4 \u0111un c\u1ee7a n\u00f3.<\/strong><\/span><\/p>\n

L\u1eddi gi\u1ea3i:<\/b><\/p>\n

<\/p>\n

V\u1eady v\u1edbi m\u1ecdi s\u1ed1 ph\u1ee9c th\u00ec ph\u1ea7n th\u1ef1c v\u00e0 ph\u1ea7n \u1ea3o c\u1ee7a n\u00f3 kh\u00f4ng v\u01b0\u1ee3t qu\u00e1 m\u00f4 \u0111un c\u1ee7a n\u00f3.<\/p>\n

B\u00e0i 8 (trang 143 SGK Gi\u1ea3i t\u00edch 12):\u00a0Th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p t\u00ednh sau:<\/strong><\/span><\/p>\n

<\/p>\n

L\u1eddi gi\u1ea3i<\/strong><\/p>\n

<\/p>\n

B\u00e0i 9 (trang 144 SGK Gi\u1ea3i t\u00edch 12):\u00a0Gi\u1ea3i c\u00e1c ph\u01b0\u01a1ng tr\u00ecnh sau tr\u00ean t\u1eadp s\u1ed1 ph\u1ee9c:<\/strong><\/span><\/p>\n

a) (3 + 4i)x + ( 1 \u2013 3i) = 2 + 5i;<\/strong><\/span><\/p>\n

b) (4 + 7i)x – (5 \u2013 2i) = 6ix<\/strong><\/span><\/p>\n

L\u1eddi gi\u1ea3i<\/strong><\/p>\n

<\/p>\n

B\u00e0i 10 (trang 144 SGK Gi\u1ea3i t\u00edch 12):\u00a0Gi\u1ea3i c\u00e1c ph\u01b0\u01a1ng tr\u00ecnh sau tr\u00ean t\u1eadp s\u1ed1 ph\u1ee9c:<\/strong><\/span><\/p>\n

a) 3z^{2<\/sup>+7z+8=0<\/strong><\/span><\/p>\n}

b) z^{4<\/sup>-8=0<\/strong><\/span><\/p>\n}

c) z^{4<\/sup>-1=0<\/p>\n}

L\u1eddi gi\u1ea3i:<\/b><\/p>\n

<\/p>\n

B\u00e0i 11 (trang 144 SGK Gi\u1ea3i t\u00edch 12):\u00a0T\u00ecm hai s\u1ed1 ph\u1ee9c, bi\u1ebft t\u1ed5ng c\u1ee7a ch\u00fang b\u1eb1ng 3 v\u00e0 t\u00edch c\u1ee7a ch\u00fang b\u1eb1ng 4.<\/strong><\/span><\/p>\n

L\u1eddi gi\u1ea3i:<\/b><\/p>\n

Gi\u1ea3 s\u1eed hai s\u1ed1 ph\u1ee9c c\u1ea7n t\u00ecm l\u00e0 z_{1<\/sub>,z2<\/sub>. Theo gi\u1ea3 thi\u1ebft ta c\u00f3:<\/p>\n}

<\/p>\n

B\u00e0i 12 (trang 144 SGK Gi\u1ea3i t\u00edch 12):\u00a0Cho hai s\u1ed1 ph\u1ee9c z_{1<\/sub>,z2<\/sub>, bi\u1ebft r\u1eb1ng z1<\/sub>+z2<\/sub>\u00a0v\u00e0 z1<\/sub>.z2<\/sub>\u00a0l\u00e0 hai s\u1ed1 th\u1ef1c. Ch\u1ee9ng t\u1ecf r\u1eb1ng z1<\/sub>,z2<\/sub>\u00a0l\u00e0 hai nghi\u1ec7m c\u1ee7a m\u1ed9t ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc hai v\u1edbi h\u1ec7 s\u1ed1 th\u1ef1c.<\/strong><\/span><\/p>\n}

L\u1eddi gi\u1ea3i:<\/b><\/p>\n

Cho c\u00e1c s\u1ed1 ph\u1ee9c z_{1<\/sub>,z2<\/sub>\u00a0khi \u0111\u00f3 z1<\/sub>,z2<\/sub>\u00a0l\u00e0 c\u00e1c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh:<\/p>\n}

(x-z_{1<\/sub>\u00a0)(x-z2<\/sub>\u00a0)=0<\/p>\n}

x^{2<\/sup>+(z_{1<\/sub>+z2<\/sub>\u00a0)x+z1<\/sub>.z2<\/sub>=0 (*)<\/p>\n}}

Theo gi\u1ea3 thi\u1ebft z_{1<\/sub>+z2<\/sub>\u00a0v\u00e0 z1<\/sub>.z2<\/sub>\u00a0l\u00e0 hai s\u1ed1 th\u1ef1c n\u00ean ph\u01b0\u01a1ng tr\u00ecnh (*) l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh b\u1eadc hai v\u1edbi h\u1ec7 s\u1ed1 th\u1ef1c.<\/p>\n}

 <\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

B\u00e0i 1 (trang 143 SGK Gi\u1ea3i t\u00edch 12):\u00a0S\u1ed1 ph\u1ee9c th\u1ecfa m\u00e3n \u0111i\u1ec1u ki\u1ec7n n\u00e0o th\u00ec c\u00f3 \u0111i\u1ec3m bi\u1ec3u di\u1ec5n \u1edf ph\u1ea7n g\u1ea1ch ch\u00e9o trong c\u00e1c h\u00ecnh a, b , c? \u00a0L\u1eddi gi\u1ea3i: a) M\u1ed7i s\u1ed1 ph\u1ee9c z = a + bi c\u00f3 \u0111i\u1ec3m bi\u1ec3u di\u1ec5n trong mi\u1ec1n g\u1ea1ch s\u1ecdc \u1edf h\u00ecnh a ph\u1ea3i th\u1ecfa m\u00e3n […]<\/p>\n","protected":false},"author":3,"featured_media":20939,"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