h\u1ecdc sinh<\/a> l\u1edbp 9.<\/p>\n\n\n\nT\u00ecm hi\u1ec3u v\u1ec1 li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng<\/p>\n\n\n\n
\u0110\u1ecbnh l\u00ed li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng<\/p>\n\n\n\n
V\u1edbi c\u00e1c s\u1ed1 a v\u00e0 b kh\u00f4ng \u00e2m ta c\u00f3 \u0111\u1eb3ng th\u1ee9c sau \u0111\u00e2y: \u221a (a.b) = \u221a a . \u221a b<\/p>\n\n\n\n
L\u01b0u \u00fd:<\/p>\n\n\n\n
V\u1edbi hai bi\u1ec3u th\u1ee9c kh\u00f4ng \u00e2m A v\u00e0 B, ch\u00fang ta c\u0169ng s\u1ebd c\u00f3 \u0111\u1eb3ng th\u1ee9c nh\u01b0 sau: \u221a (A.B) = \u221a A .\u221a B<\/p>\n\n\n\n
N\u1ebfu kh\u00f4ng c\u00f3 \u0111i\u1ec1u ki\u1ec7n A v\u00e0 B kh\u00f4ng \u00e2m th\u00ec kh\u00f4ng th\u1ec3 vi\u1ebft \u0111\u01b0\u1ee3c \u0111\u1eb1ng th\u1ee9c tr\u00ean.<\/p>\n\n\n\n
V\u00ed d\u1ee5: \u221a [(-9).(-4)] \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh nh\u01b0ng \u0111\u1eb3ng th\u1ee9c \u221a (-9) . \u221a (-4) kh\u00f4ng x\u00e1c \u0111\u1ecbnh.<\/p>\n\n\n\n
\u00c1p d\u1ee5ng li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 khai ph\u01b0\u01a1ng<\/p>\n\n\n\n
Khi ti\u1ebfn h\u00e0nh gi\u1ea3i c\u00e1c b\u00e0i to\u00e1n c\u00f3 li\u00ean quan \u0111\u1ebfn li\u00ean h\u1ec7 ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng, ch\u00fang ta s\u1ebd th\u1ef1c hi\u1ec7n theo c\u00e1c quy t\u1eafc sau \u0111\u00e2y:<\/p>\n\n\n\n
Quy t\u1eafc khai ph\u01b0\u01a1ng m\u1ed9t t\u00edch<\/p>\n\n\n\n
Mu\u1ed1n khai ph\u01b0\u01a1ng m\u1ed9t t\u00edch c\u1ee7a nh\u1eefng s\u1ed1 kh\u00f4ng \u00e2m, ta c\u00f3 th\u1ec3 khai ph\u01b0\u01a1ng t\u1eebng th\u1eeba s\u1ed1 r\u1ed3i nh\u00e2n c\u00e1c k\u1ebft qu\u1ea3 v\u1edbi nhau.<\/p>\n\n\n\n
M\u1edf r\u1ed9ng: V\u1edbi c\u00e1c s\u1ed1 a, b, c kh\u00f4ng \u00e2m ta c\u00f3: \u221a (a.b.c) = \u221a a . \u221a b . \u221a c<\/p>\n\n\n\n
Quy t\u1eafc nh\u00e2n c\u00e1c c\u0103n b\u1eadc hai<\/p>\n\n\n\n
Mu\u1ed1n nh\u00e2n c\u00e1c c\u0103n b\u1eadc hai c\u1ee7a nh\u1eefng s\u1ed1 kh\u00f4ng \u00e2m, ta c\u00f3 th\u1ec3 nh\u00e2n c\u00e1c s\u1ed1 d\u01b0\u1edbi d\u1ea5u c\u0103n v\u1edbi nhau r\u1ed3i khai ph\u01b0\u01a1ng k\u1ebft qu\u1ea3 \u0111\u00f3.<\/p>\n\n\n\n
M\u1edf r\u1ed9ng: V\u1edbi c\u00e1c s\u1ed1 a, b, c kh\u00f4ng \u00e2m ta c\u00f3: \u221a a . \u221a b . \u221a c = \u221a (a.b.c)<\/p>\n\n\n\n
V\u1edbi bi\u1ec3u th\u1ee9c A kh\u00f4ng \u00e2m, ta c\u00f3: (\u221a A)2 = \u221a (A2) = A<\/p>\n\n\n\n
C\u00e1c d\u1ea1ng b\u00e0i li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng c\u01a1 b\u1ea3n<\/p>\n\n\n\n
D\u1ea1ng 1: Th\u1ef1c hi\u1ec7n ph\u00e9p t\u00ednh<\/p>\n\n\n\n
\u00c1p d\u1ee5ng c\u00f4ng th\u1ee9c khai ph\u01b0\u01a1ng m\u1ed9t t\u00edch v\u00e0 khai ph\u01b0\u01a1ng m\u1ed9t th\u01b0\u01a1ng<\/p>\n\n\n\n
V\u1edbi hai bi\u1ec3u th\u1ee9c A, B kh\u00f4ng \u00e2m ta c\u00f3 \u221a (A.B) = \u221a A .\u221a B<\/p>\n\n\n\n
V\u1edbi bi\u1ec3u th\u1ee9c A kh\u00f4ng \u00e2m v\u00e0 bi\u1ec3u th\u1ee9c B d\u01b0\u01a1ng ta c\u00f3 \u221a (A\/B) = \u221a A \/ \u221a B<\/p>\n\n\n\n
V\u00ed d\u1ee5:<\/p>\n\n\n\n
\u221a 32 + \u221a 8 = \u221a (16.2) + \u221a (4.2) = \u221a 16 . \u221a 2 + \u221a 4 . \u221a 2 = 4\u221a 2 + 2\u221a 2 = 6\u221a 2<\/p>\n\n\n\n
D\u1ea1ng 2: R\u00fat g\u1ecdn bi\u1ec3u th\u1ee9c<\/p>\n\n\n\n
Ph\u01b0\u01a1ng ph\u00e1p:<\/p>\n\n\n\n
\u2013 \u00c1p d\u1ee5ng c\u00f4ng th\u1ee9c khai ph\u01b0\u01a1ng m\u1ed9t t\u00edch v\u00e0 khai ph\u01b0\u01a1ng m\u1ed9t th\u01b0\u01a1ng<\/p>\n\n\n\n
V\u1edbi hai bi\u1ec3u th\u1ee9c A, B kh\u00f4ng \u00e2m ta c\u00f3 \u221a (A.B) = \u221a A .\u221a B<\/p>\n\n\n\n
V\u1edbi bi\u1ec3u th\u1ee9c A kh\u00f4ng \u00e2m v\u00e0 bi\u1ec3u th\u1ee9c B d\u01b0\u01a1ng ta c\u00f3 \u221a (A\/B) = \u221a A \/ \u221a B<\/p>\n\n\n\n
\u2013 \u00c1p d\u1ee5ng h\u1eb1ng \u0111\u1eb3ng th\u1ee9c \u221a (A2) = |A|<\/p>\n\n\n\n
V\u00ed d\u1ee5:<\/p>\n\n\n\n
D\u1ea1ng 3: Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh<\/p>\n\n\n\n
Ph\u01b0\u01a1ng ph\u00e1p:<\/p>\n\n\n\n
S\u1eed d\u1ee5ng c\u00f4ng th\u1ee9c khai ph\u01b0\u01a1ng m\u1ed9t t\u00edch v\u00e0 khai ph\u01b0\u01a1ng m\u1ed9t th\u01b0\u01a1ng \u0111\u1ec3 \u0111\u01b0a ph\u01b0\u01a1ng tr\u00ecnh \u0111\u00e3 cho v\u1ec1 c\u00e1c d\u1ea1ng quen thu\u1ed9c:<\/p>\n\n\n\n
Ghi nh\u1edb l\u00fd thuy\u1ebft \u0111\u1ec3 \u00e1p d\u1ee5ng v\u00e0o gi\u1ea3i c\u00e1c b\u00e0i t\u1eadp nhanh ch\u00f3ng<\/p>\n\n\n\n
Li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p chia v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng<\/p><\/blockquote>\n\n\n\n
M\u1ed9t s\u1ed1 b\u00e0i to\u00e1n 9 li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng<\/p>\n\n\n\n
Gi\u1ea3i b\u00e0i 17 trang 14 SGK To\u00e1n 9 t\u1eadp 1<\/p>\n\n\n\n
Gi\u1ea3i b\u00e0i 18 trang 14 \u2013 SGK To\u00e1n l\u1edbp 9 t\u1eadp 1<\/p>\n\n\n\n
Gi\u1ea3i b\u00e0i 19 trang 15 \u2013 SGK To\u00e1n l\u1edbp 9 t\u1eadp 1<\/p>\n\n\n\n
C\u00e1ch l\u00e0m b\u00e0i t\u1eadp li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng nhanh<\/p>\n\n\n\n
M\u1ed7i m\u1ed9t d\u1ea1ng to\u00e1n s\u1ebd l\u1ea1i c\u00f3 c\u00e1ch gi\u1ea3i kh\u00e1c nhau v\u00e0 bu\u1ed9c ch\u00fang ta c\u1ea7n ph\u1ea3i ghi nh\u1edb \u0111\u1ec3 th\u1ef1c hi\u1ec7n. V\u1eady l\u00e0m sao \u0111\u1ec3 c\u00f3 th\u1ec3 gi\u1ea3i c\u00e1c b\u00e0i t\u1eadp to\u00e1n li\u00ean quan \u0111\u1ebfn ch\u1ee7 \u0111\u1ec1 li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng nhanh ch\u00f3ng, ch\u00ednh x\u00e1c?<\/p>\n\n\n\n
Vietlearn s\u1ebd gi\u00fap b\u1ea1n tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi n\u00e0y. Nguy\u00ean t\u1eafc chung \u0111\u1ec3 h\u1ecdc gi\u1ecfi to\u00e1n v\u00e0 \u0111\u1ea1t \u0111i\u1ec3m cao m\u00f4n to\u00e1n tr\u00ean l\u1edbp th\u00ec \u0111i\u1ec1u \u0111\u1ea7u ti\u00ean b\u1ea1n c\u1ea7n ph\u1ea3i n\u1eafm v\u1eefng t\u1ea5t c\u1ea3 c\u00e1c d\u1ea1ng b\u00e0i v\u00e0 luy\u1ec7n cho th\u00e0nh ph\u1ea3n x\u1ea1. \u0110\u1ebfn khi b\u1eaft g\u1eb7p d\u1ea1ng to\u00e1n \u0111\u00f3, ngay l\u1eadp t\u1ee9c ch\u00fang ta c\u00f3 th\u1ec3 gi\u1ea3i quy\u1ebft \u0111\u01b0\u1ee3c ch\u00fang.<\/p>\n\n\n\n
\u0110\u1eb7c bi\u1ec7t hi\u1ec7n nay, ch\u00fang ta \u0111ang chuy\u1ec3n d\u1ea7n sang ph\u01b0\u01a1ng ph\u00e1p thi tr\u1eafc nghi\u1ec7m th\u00ec vi\u1ec7c l\u00e0m sao \u0111\u1ec3 gi\u1ea3i \u0111\u01b0\u1ee3c c\u00e1c b\u00e0i t\u1eadp to\u00e1n li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng nhanh l\u1ea1i c\u00e0ng c\u1ea7n thi\u1ebft h\u01a1n.<\/p>\n\n\n\n
Ba b\u01b0\u1edbc \u0111\u1ec3 gi\u1ea3i th\u00e0nh th\u1ee5c m\u1ed9t d\u1ea1ng b\u00e0i nh\u01b0 sau:<\/p>\n\n\n\n
B\u01b0\u1edbc 1: L\u00e0m quen<\/p>\n\n\n\n
Tr\u01b0\u1edbc h\u1ebft, b\u1ea1n c\u1ea7n t\u00ecm hi\u1ec3u v\u1ec1 l\u00fd thuy\u1ebft c\u1ee7a ki\u1ebfn th\u1ee9c \u0111\u00f3 th\u00f4ng qua \u0111\u1ecbnh ngh\u0129a, kh\u00e1i ni\u1ec7m, v\u00ed d\u1ee5, nguy\u00ean l\u00fd\u2026 Ph\u1ea7n l\u00fd thuy\u1ebft c\u1ee7a m\u1ed7i m\u1ed9t d\u1ea1ng b\u00e0i s\u1ebd r\u1ea5t ng\u1eafn n\u00ean vi\u1ec7c l\u00e0m quen v\u1edbi ch\u00fang kh\u00f4ng qu\u00e1 ph\u1ee9c t\u1ea1p.<\/p>\n\n\n\n
B\u01b0\u1edbc 2: N\u1eafm v\u1eefng<\/p>\n\n\n\n
Sau khi \u0111\u00e3 c\u00f3 b\u01b0\u1edbc l\u00e0m quen ban \u0111\u1ea7u, h\u00e3y t\u00ecm hi\u1ec3u v\u1ec1 c\u00e1c d\u1ea1ng to\u00e1n th\u01b0\u1eddng g\u1eb7p c\u0169ng nh\u01b0 c\u00f4ng th\u1ee9c \u0111\u1ec3 gi\u1ea3i quy\u1ebft d\u1ea1ng b\u00e0i \u0111\u00f3. T\u1ed1t nh\u1ea5t l\u00e0 h\u00e3y h\u1ecdc gi\u1ea3i m\u1ed9t s\u1ed1 b\u00e0i t\u1eadp c\u01a1 b\u1ea3n \u1edf trong SGK to\u00e1n l\u1edbp 9 b\u00e0i li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng. T\u1eeb \u0111\u00f3, ch\u00fang ta s\u1ebd n\u1eafm \u0111\u01b0\u1ee3c c\u00e1ch l\u00e0m c\u01a1 b\u1ea3n v\u00e0 \u00e1p d\u1ee5ng \u0111\u1ec3 gi\u1ea3i \u0111\u01b0\u1ee3c nhi\u1ec1u lo\u1ea1i b\u00e0i t\u1eadp h\u01a1n.<\/p>\n\n\n\n
B\u01b0\u1edbc 3: \u00c1p d\u1ee5ng<\/p>\n\n\n\n
\u00c1p d\u1ee5ng c\u00e1c c\u00f4ng th\u1ee9c, kinh nghi\u1ec7m m\u00e0 b\u1ea3n th\u00e2n r\u00fat ra khi l\u00e0m c\u00e1c b\u00e0i t\u1eadp c\u01a1 b\u1ea3n trong SGK. H\u00e3y n\u00e2ng d\u1ea7n t\u1eebng c\u1ea5p \u0111\u1ed9 kh\u00f3. Kh\u00f4ng ch\u1ec9 \u00e1p d\u1ee5ng v\u00e0 th\u1ef1c hi\u1ec7n m\u1ed7i m\u1ed9t c\u00f4ng th\u1ee9c \u0111\u01a1n gi\u1ea3n \u0111\u00f3 n\u1eefa m\u00e0 ph\u1ea3i \u00e1p d\u1ee5ng c\u00f4ng th\u1ee9c \u0111\u00f3 v\u00e0o b\u00e0i t\u1eadp \u0111a d\u1ea1ng h\u01a1n. Nh\u01b0 v\u1eady \u0111\u1ebfn l\u00fac thi ch\u00fang ta m\u1edbi c\u00f3 th\u1ec3 l\u00e0m m\u1ed9t c\u00e1ch nhanh ch\u00f3ng. Nh\u01b0 v\u1eady, c\u00e1ch t\u1ed1t nh\u1ea5t \u0111\u1ec3 b\u1ea1n c\u00f3 th\u1ec3 h\u1ecdc \u0111\u01b0\u1ee3c t\u1ed1t m\u00f4n To\u00e1n \u0111\u00f3 ch\u00ednh l\u00e0 l\u00e0m th\u1eadt nhi\u1ec1u b\u00e0i t\u1eadp \u0111\u1ec3 quen v\u1edbi c\u00e1ch gi\u1ea3i c\u1ee7a c\u00e1c b\u00e0i to\u00e1n. Ch\u1ec9 c\u1ea7n l\u01a1 l\u00e0 m\u1ed9t ch\u00fat l\u00e0 ch\u00fang ta \u0111\u00e3 c\u00f3 th\u1ec3 qu\u00ean \u0111i c\u00e1ch l\u00e0m b\u00e0i ngay \u0111\u1ea5y.<\/p>\n\n\n\n
Truy c\u1eadp v\u00e0o Vietlearn \u0111\u1ec3 h\u1ecdc to\u00e1n t\u1ed1t h\u01a1n<\/p>\n\n\n\n
Tr\u00ean \u0111\u00e2y l\u00e0 nh\u1eefng l\u00fd thuy\u1ebft v\u1ec1 li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng c\u0169ng nh\u01b0 c\u00e1ch \u0111\u1ec3 gi\u1ea3i d\u1ea1ng b\u00e0i t\u1eadp n\u00e0y nhanh ch\u00f3ng. \u0110\u1ec3 h\u1ecdp t\u1ed1t h\u01a1n m\u00f4n To\u00e1n, b\u1ea1n c\u00f3 th\u1ec3 t\u00ecm hi\u1ec3u th\u00eam h\u1ec7 th\u1ed1ng ki\u1ebfn th\u1ee9c v\u00e0 c\u00e1c b\u00e0i t\u1eadp t\u1ea1i Vietlearn.org\/.<\/p>\n\n\n\n
T\u00ecm hi\u1ec3u th\u00eam:<\/p>\n\n\n\n
C\u0103n th\u1ee9c b\u1eadc hai v\u00e0 h\u1eb1ng \u0111\u1eb3ng th\u1ee9c<\/p>\n\n\n\n
C\u0103n b\u1eadc hai l\u1edbp 9 \u2013 Kh\u00e1i ni\u1ec7m v\u00e0 c\u00e1c \u0111\u1ecbnh l\u00fd li\u00ean quan<\/p>\n\n\n\n
Bi\u1ebfn \u0111\u1ed5i \u0111\u01a1n gi\u1ea3n bi\u1ec3u th\u1ee9c ch\u1ee9a c\u0103n b\u1eadc hai \u2013 C\u00f9ng Vietlearn c<\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"
Ghi ch\u00fa: T\u00e0i li\u1ec7u tr\u00edch d\u1eabn N\u1ebfu b\u1ea1n \u0111ang t\u00ecm ki\u1ebfm c\u00e1c t\u00e0i li\u1ec7u quan quan \u0111\u1ebfn ki\u1ebfn th\u1ee9c v\u1ec1 li\u00ean h\u1ec7 gi\u1eefa ph\u00e9p nh\u00e2n v\u00e0 ph\u00e9p khai ph\u01b0\u01a1ng th\u00ec b\u00e0i vi\u1ebft n\u00e0y l\u00e0 d\u00e0nh cho b\u1ea1n. Vietlearn s\u1ebd gi\u00fap b\u1ea1n t\u1ed5ng h\u1ee3p l\u1ea1i c\u00e1c ki\u1ebfn th\u1ee9c li\u00ean quan \u0111\u1ebfn ch\u1ee7 \u0111\u1ec1 n\u00e0y v\u00e0 h\u01b0\u1edbng […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[9],"tags":[],"class_list":["post-1061","post","type-post","status-publish","format-standard","hentry","category-toan-hoc"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/1061","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/comments?post=1061"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/1061\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=1061"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=1061"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=1061"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}