Tr\u00ean \u0111\u00e2y ch\u00fang ta v\u1eeba nghi\u00ean c\u1ee9u c\u00e1ch th\u1ee9c ti\u1ebfn h\u00e0nh th\u00ed nghi\u1ec7m theo ph\u01b0\u01a1ng \u00e1n g\u1ea5p gi\u1ea5y. Th\u1ebf t\u1ea1i sao trong ph\u01b0\u01a1ng \u00e1n th\u00ed nghi\u1ec7m n\u00e0y ta l\u1ea1i d\u00f9ng con s\u1ed1 0,618?<\/p>\n\n\n\n
Trong c\u00e1ch ch\u1ecdn t\u1ed1i \u01b0u, ch\u00fang ta \u0111\u00e3 x\u1eed l\u00ed c\u00e1c t\u00ecnh hu\u1ed1ng sau: V\u1edbi m\u1ed9t nh\u00e2n t\u1ed1 n\u00e0o \u0111\u00f3 v\u00e0 t\u1ea1i m\u1ed9t \u0111i\u1ec3m n\u00e0o \u0111\u00f3 nh\u00e2n t\u1ed1 \u0111\u00f3 ch\u1ee9ng t\u1ecf c\u00f3 \u1ea3nh h\u01b0\u1edfng t\u1ed1t nh\u1ea5t, m\u00e0 khi t\u0103ng ho\u1eb7c gi\u1ea3m gi\u00e1 tr\u1ecb c\u1ee7a nh\u00e2n t\u1ed1 th\u00ec c\u00e1c ch\u1ec9 ti\u00eau \u0111\u1ec1u gi\u1ea3m. Gi\u1ea3 s\u1eed khi ch\u1ecdn hai \u0111i\u1ec3m b\u1ea5t k\u00ec X1 v\u00e0 X2 l\u00e0m th\u00ed nghi\u1ec7m ta nh\u1eadn \u0111\u01b0\u1ee3c k\u1ebft qu\u1ea3 Y1 k\u00e9m h\u01a1n Y2, ta c\u00f3 th\u1ec3 b\u1ecf \u0111i c\u00e1c gi\u00e1 tr\u1ecb \u1edf b\u00ean tr\u00e1i X1\u01a1 m\u00e0 kh\u00f4ng b\u1ecf m\u1ea5t \u0111i\u1ec3m t\u1ed1i \u01b0u. Trong ph\u01b0\u01a1ng \u00e1n g\u1ea5p gi\u1ea5y vi\u1ec7c c\u1eaft b\u1ecf ph\u1ea7n b\u0103ng gi\u1ea5y c\u0169ng ch\u00ednh l\u00e0 v\u00ec l\u00ed do \u0111\u00f3.<\/p>\n\n\n\n
\u0110\u1ec3 gi\u1ea3m b\u1edbt s\u1ed1 l\u1ea7n th\u00ed nghi\u1ec7m ph\u1ea3i x\u00e9t ch\u1ecdn \u0111i\u1ec3m th\u00ed nghi\u1ec7m \u0111\u1ea7u ti\u00ean?<\/p>\n\n\n\n
N\u1ebfu ta d\u00f9ng (0,1) \u0111\u1ec3 bi\u1ec3u di\u1ec5n ph\u1ea1m vi th\u00ed nghi\u1ec7m, tr\u01b0\u1edbc h\u1ebft ta ch\u1ecdn \u0111i\u1ec3m X nh\u01b0 h\u00ecnh v\u1ebd, l\u1ea1i ch\u1ecdn \u0111i\u1ec3m Y ti\u1ebfn h\u00e0nh th\u00ed nghi\u1ec7m so s\u00e1nh. Do s\u1ef1 xu\u1ea5t hi\u1ec7n t\u00edn hi\u1ec7u t\u1ed1t \u1edf hai \u0111i\u1ec3m l\u00e0 c\u00f3 kh\u1ea3 n\u0103ng nh\u01b0 nhau, th\u00ec vi\u1ec7c c\u1eaft b\u1ecf ph\u1ea7n (0, Y) ho\u1eb7c (X, 1) l\u00e0 c\u00f3 kh\u1ea3 n\u0103ng nh\u01b0 nhau. V\u00ec c\u00e1c ph\u1ea7n c\u1eaft l\u00e0 c\u00f3 \u0111\u1ed9 d\u00e0i nh\u01b0 nhau n\u00ean Y = 1- X<\/p>\n\n\n\n
N\u1ebfu c\u1eaft b\u1ecf ph\u1ea7n (X, 1) gi\u1eef l\u1ea1i ph\u1ea7n (0, X) trong \u0111\u00f3 c\u00f3 \u0111i\u1ec3m Y c\u0169ng t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi \u0111i\u1ec3m X trong kho\u1ea3ng (0, 1). Do \u0111\u00f3:<\/p>\n\n\n\n
Y\/X = X\/1 hay Y = X2 thay Y = 1 – X ta c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh X2 + X – 1 = 0 Nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr\u00ecnh s\u1ebd l\u00e0:<\/p>\n\n\n\n
Con s\u1ed1 0,618 trong ph\u01b0\u01a1ng th\u1ee9c c\u1eaft gi\u1ea5y ch\u00ednh l\u00e0 gi\u00e1 tr\u1ecb g\u1ea7n \u0111\u00fang c\u1ee7a con s\u1ed1 n\u00e0y. Trong ph\u01b0\u01a1ng ph\u00e1p c\u1eaft gi\u1ea5y ta l\u1ea5y m\u1ed9t \u0111\u1ed9 d\u00e0i x\u00e1c \u0111\u1ecbnh chia l\u00e0m hai ph\u1ea7n, trong \u0111\u00f3 c\u00f3 m\u1ed9t ph\u1ea7n c\u00f3 \u0111\u1ed9 d\u00e0i b\u1eb1ng b\u1ed9i s\u1ed1 c\u1ee7a 0,618. Theo gi\u00e1c \u0111\u1ed9 h\u00ecnh h\u1ecdc ng\u01b0\u1eddi ta g\u1ecdi \u0111\u00e2y l\u00e0 con s\u1ed1 v\u00e0ng (ho\u00e0ng kim), c\u00f2n \u0111i\u1ec3m chia \u1ee9ng v\u1edbi con s\u1ed1 \u0111\u00f3 l\u00e0 \u0111i\u1ec3m chia c\u1eaft v\u00e0ng.<\/p>\n\n\n\n
V\u00ec v\u1eady, ph\u01b0\u01a1ng ph\u00e1p tuy\u1ec3n ch\u1ecdn n\u00e0y l\u00e0 \u201cph\u01b0\u01a1ng ph\u00e1p chia c\u1eaft v\u00e0ng\u201d hay \u201cti\u1ebft di\u1ec7n v\u00e0ng\u201d ( btv).<\/p>\n\n\n\n
T\u1eeb kho\u00e1: Ph\u01b0\u01a1ng ph\u00e1p g\u1ea5p gi\u1ea5y; Ph\u01b0\u01a1ng ph\u00e1p ch\u1ecdn t\u1ed1i \u01b0u; \u0110i\u1ec3m chia c\u1eaft v\u00e0ng (ho\u00e0ng kim); Ph\u01b0\u01a1ng ph\u00e1p chia c\u1eaft v\u00e0ng.<\/p>\n\n\n\n
<\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"
Tr\u00ean \u0111\u00e2y ch\u00fang ta v\u1eeba nghi\u00ean c\u1ee9u c\u00e1ch th\u1ee9c ti\u1ebfn h\u00e0nh th\u00ed nghi\u1ec7m theo ph\u01b0\u01a1ng \u00e1n g\u1ea5p gi\u1ea5y. Th\u1ebf t\u1ea1i sao trong ph\u01b0\u01a1ng \u00e1n th\u00ed nghi\u1ec7m n\u00e0y ta l\u1ea1i d\u00f9ng con s\u1ed1 0,618? Trong c\u00e1ch ch\u1ecdn t\u1ed1i \u01b0u, ch\u00fang ta \u0111\u00e3 x\u1eed l\u00ed c\u00e1c t\u00ecnh hu\u1ed1ng sau: V\u1edbi m\u1ed9t nh\u00e2n t\u1ed1 n\u00e0o \u0111\u00f3 v\u00e0 t\u1ea1i […]<\/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":[15,9],"tags":[],"class_list":["post-7698","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-toan-hoc"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/7698","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=7698"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/7698\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=7698"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=7698"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=7698"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}