M\u1ecdi ng\u01b0\u1eddi \u0111\u1ec1u r\u1ea5t quen thu\u1ed9c v\u1edbi b\u1ed1n ph\u00e9p t\u00ednh s\u1ed1 h\u1ecdc v\u00e0 d\u1ea5u b\u1eb1ng. Th\u1ebf b\u1ea1n c\u00f3 bi\u1ebft lai l\u1ecbch c\u1ee7a c\u00e1c k\u00ed hi\u1ec7u n\u00e0y kh\u00f4ng?<\/p>\n\n\n\n
V\u00e0o th\u1eddi xa x\u01b0a, \u1edf Hy L\u1ea1p v\u00e0 \u1ea5n \u0110\u1ed9 ng\u01b0\u1eddi ta th\u01b0\u1eddng vi\u1ebft c\u00e1c s\u1ed1 \u1edf c\u1ea1nh nhau \u0111\u1ec3 bi\u1ec3u di\u1ec5n ph\u00e9p c\u1ed9ng. V\u00ed d\u1ee5 nh\u01b0 3 + 1\/4 s\u1ebd vi\u1ebft l\u00e0 31\/4 .<\/p>\n\n\n\n
Ng\u00e0y nay ng\u01b0\u1eddi ta c\u00f2n th\u1ea5y v\u1ebft t\u00edch c\u1ee7a c\u00e1ch vi\u1ebft n\u00e0y khi vi\u1ebft s\u1ed1 ph\u00e2n s\u1ed1. H\u1ecd c\u00f9ng vi\u1ebft hai s\u1ed1 c\u00e1ch xa nhau m\u1ed9t kho\u1ea3ng \u0111\u1ec3 bi\u1ec3u di\u1ec5n ph\u00e9p tr\u1eeb, v\u00ed d\u1ee5 vi\u1ebft 6 1\/5 ch\u00ednh l\u00e0 \u0111\u1ec3 bi\u1ec3u di\u1ec5n 6 – 1\/5 .<\/p>\n\n\n\n
V\u00e0o th\u1eddi Trung C\u1ed5, th\u01b0\u01a1ng nghi\u1ec7p Ch\u00e2u \u00c2u r\u1ea5t ph\u00e1t \u0111\u1ea1t. M\u1ed9t s\u1ed1 th\u01b0\u01a1ng nh\u00e2n th\u01b0\u1eddng \u0111\u00e1nh d\u1ea5u \u201c+\u201d tr\u00ean c\u00e1c h\u00f2m \u0111\u1ec3 bi\u1ec3u th\u1ecb tr\u1ecdng l\u01b0\u1ee3ng qu\u00e1 n\u1eb7ng, c\u00f2n v\u1ebd d\u1ea5u \u201c – \u201c \u0111\u1ec3 ch\u1ec9 c\u00e1i th\u00f9ng l\u00e0 nh\u1eb9 v\u00e0 kh\u00f4ng \u0111\u1ee7 tr\u1ecdng l\u01b0\u1ee3ng. Th\u1eddi Ph\u1ee5c h\u01b0ng \u1edf Italia, Leonardo de Vinci \u0111\u00e3 ghi c\u00e1c d\u1ea5u \u201c+\u201d v\u00e0 d\u1ea5u \u201c – \u201d l\u00ean c\u00e1c t\u00e1c ph\u1ea9m c\u1ee7a m\u00ecnh. N\u0103m 1489, m\u1ed9t ng\u01b0\u1eddi \u0110\u1ee9c l\u00e0 Wideman \u0111\u00e3 ch\u00ednh th\u1ee9c d\u00f9ng c\u00e1c k\u00ed hi\u1ec7u \u201c+\u201d v\u00e0 \u201c-\u201d \u0111\u1ec3 bi\u1ec3u di\u1ec5n ph\u00e9p t\u00ednh c\u1ed9ng v\u00e0 ph\u00e9p t\u00ednh tr\u1eeb trong t\u00e1c ph\u1ea9m c\u1ee7a m\u00ecnh. V\u1ec1 sau nh\u1edd nh\u00e0 to\u00e1n h\u1ecdc Ph\u00e1p Viete h\u1ebft s\u1ee9c tuy\u00ean truy\u1ec1n v\u00e0 c\u1ed5 v\u0169, hai k\u00ed hi\u1ec7u n\u00e0y m\u1edbi \u0111\u01b0\u1ee3c ph\u1ed5 c\u1eadp v\u00e0 \u0111\u1ebfn n\u0103m 1603 m\u1edbi \u0111\u01b0\u1ee3c m\u1ecdi ng\u01b0\u1eddi th\u1eeba nh\u1eadn.<\/p>\n\n\n\n
\u1ede Trung Qu\u1ed1c th\u1eddi x\u01b0a ng\u01b0\u1eddi ta \u0111\u00e3 d\u00f9ng th\u1ebb t\u00ednh v\u00e0 bi t\u00ednh \u0111\u1ec3 ti\u1ebfn h\u00e0nh c\u00e1c ph\u00e9p c\u1ed9ng, tr\u1eeb, nh\u00e2n v\u00e0 chia nh\u01b0ng ch\u01b0a \u0111\u1eb7t ra c\u00e1c k\u00ed hi\u1ec7u chuy\u00ean m\u00f4n \u0111\u1ec3 k\u00ed hi\u1ec7u c\u00e1c ph\u00e9p t\u00ednh. H\u00e3y l\u1ea5y \u0111\u1eb3ng th\u1ee9c \u201cL\u00fd Thi\u1ec7n Lan\u201d n\u1ed5i ti\u1ebfng c\u1ee7a nh\u00e0 to\u00e1n h\u1ecdc L\u00fd Thi\u1ec7n Lan l\u00e0m v\u00ed d\u1ee5. L\u00fd Thi\u1ec7n Lan \u0111\u00e3 d\u00f9ng k\u00ed hi\u1ec7u \u201c\uf05e\u201d \u0111\u1ec3 bi\u1ec3u di\u1ec5n d\u1ea5u \u201c+\u201d v\u00e0 d\u1ea5u T \u0111\u1ec3 bi\u1ec3u di\u1ec5n d\u1ea5u \u201c-\u201d. Nh\u01b0ng \u1edf c\u00e1c s\u00e1ch to\u00e1n xu\u1ea5t b\u1ea3n v\u00e0o cu\u1ed1i \u0111\u1eddi Thanh, ng\u01b0\u1eddi ta \u0111\u00e3 d\u00f9ng c\u00e1ch m\u00f4 t\u1ea3 thay cho k\u00ed hi\u1ec7u. Sau C\u00e1ch m\u1ea1ng T\u00e2n H\u1ee3i, ng\u01b0\u1eddi ta m\u1edbi d\u00f9ng k\u00ed hi\u1ec7u nh\u01b0 ng\u00e0y nay.<\/p>\n\n\n\n
C\u00f2n vi\u1ec7c s\u1eed d\u1ee5ng d\u1ea5u x v\u00e0 d\u1ea5u \u00f7 th\u00ec ph\u1ea3i \u0111\u1ebfn 300 n\u0103m sau n\u1eefa. N\u0103m 1631 Wiliam Autelite l\u00e0 ng\u01b0\u1eddi \u0111\u1ea7u ti\u00ean \u0111\u00e3 d\u00f9ng d\u1ea5u \u201cx\u201d \u0111\u1ec3 bi\u1ec3u di\u1ec5n ph\u00e9p nh\u00e2n, sau n\u00e0y ng\u01b0\u1eddi ta m\u1edbi s\u1eed d\u1ee5ng ph\u1ed5 bi\u1ebfn cho \u0111\u1ebfn ng\u00e0y nay.<\/p>\n\n\n\n
V\u00e0o th\u1eddi Trung C\u1ed5, to\u00e1n h\u1ecdc \u1edf c\u00e1c n\u01b0\u1edbc Ar\u1eadp t\u01b0\u01a1ng \u0111\u1ed1i ph\u00e1t tri\u1ec3n. Nh\u00e0 to\u00e1n h\u1ecdc l\u1edbn Watmet \u0111\u00e3 d\u00f9ng k\u00ed hi\u1ec7u \u201c3\/4\u201d \u0111\u1ec3 bi\u1ec3u di\u1ec5n ph\u00e9p chia c\u1ee7a 3 cho 4. Nhi\u1ec1u ng\u01b0\u1eddi cho r\u1eb1ng c\u00e1ch vi\u1ebft ph\u00e2n s\u1ed1 nh\u01b0 ng\u00e0y nay l\u00e0 xu\u1ea5t ph\u00e1t t\u1eeb c\u00e1ch vi\u1ebft \u0111\u00f3. M\u00e3i \u0111\u1ebfn n\u0103m 1630 m\u1edbi xu\u1ea5t hi\u1ec7n d\u1ea5u \u201c \u00f7\u201d \u0111\u1ec3 bi\u1ec3u di\u1ec5n ph\u00e9p t\u00ednh chia.<\/p>\n\n\n\n
Ng\u00e0y nay \u1edf \u0111a s\u1ed1 c\u00e1c qu\u1ed1c gia, ng\u01b0\u1eddi ta d\u00f9ng c\u00e1c k\u00ed hi\u1ec7u \u201c+\u201d v\u00e0 \u201c-\u201d \u0111\u1ec3 bi\u1ec3u di\u1ec5n ph\u00e9p t\u00ednh c\u1ed9ng v\u00e0 ph\u00e9p t\u00ednh tr\u1eeb. C\u00f2n d\u1ea5u \u201cx\u201d v\u00e0 d\u1ea5u \u201c\u00f7\u201d kh\u00f4ng ph\u1ea3i \u0111\u01b0\u1ee3c d\u00f9ng th\u1eadt ph\u1ed5 bi\u1ebfn \u1edf nhi\u1ec1u n\u01b0\u1edbc ng\u01b0\u1eddi ta d\u00f9ng d\u1ea5u \u201c.\u201d thay cho d\u1ea5u \u201cx\u201d v\u00e0 d\u1ea5u \u201c: \u201d thay cho d\u1ea5u \u00f7.<\/p>\n\n\n\n
C\u00f2n d\u1ea5u \u201c=\u201d \u0111\u01b0\u1ee3c ra \u0111\u1eddi t\u1eeb bao gi\u1edd v\u00e0 \u1edf \u0111\u00e2u? Ng\u01b0\u1eddi Babilon v\u00e0 Ai C\u1eadp \u0111\u00e3 t\u1eebng d\u00f9ng c\u00e1c k\u00ed hi\u1ec7u kh\u00e1c nhau \u0111\u1ec3 bi\u1ec3u di\u1ec5n s\u1ef1 b\u1eb1ng nhau. C\u00f2n d\u1ea5u \u201c=\u201d \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng s\u1edbm nh\u1ea5t trong t\u00e1c ph\u1ea9m \u201cH\u00f2n \u0111\u00e1 m\u00e0i tr\u00ed tu\u1ec7\u201d c\u1ee7a Reked. Th\u1ebf nh\u01b0ng d\u1ea5u \u201c=\u201d m\u00e3i \u0111\u1ebfn th\u1ebf k\u1ec9 XVIII m\u1edbi \u0111\u01b0\u1ee3c ph\u1ed5 bi\u1ebfn r\u1ed9ng r\u00e3i.<\/p>\n\n\n\n
T\u1eeb kho\u00e1: K\u00ed hi\u1ec7u ph\u00e9p t\u00ednh s\u1ed1 h\u1ecdc.<\/p>\n\n\n\n
<\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"
M\u1ecdi ng\u01b0\u1eddi \u0111\u1ec1u r\u1ea5t quen thu\u1ed9c v\u1edbi b\u1ed1n ph\u00e9p t\u00ednh s\u1ed1 h\u1ecdc v\u00e0 d\u1ea5u b\u1eb1ng. Th\u1ebf b\u1ea1n c\u00f3 bi\u1ebft lai l\u1ecbch c\u1ee7a c\u00e1c k\u00ed hi\u1ec7u n\u00e0y kh\u00f4ng? V\u00e0o th\u1eddi xa x\u01b0a, \u1edf Hy L\u1ea1p v\u00e0 \u1ea5n \u0110\u1ed9 ng\u01b0\u1eddi ta th\u01b0\u1eddng vi\u1ebft c\u00e1c s\u1ed1 \u1edf c\u1ea1nh nhau \u0111\u1ec3 bi\u1ec3u di\u1ec5n ph\u00e9p c\u1ed9ng. V\u00ed d\u1ee5 nh\u01b0 3 […]<\/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-7642","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\/7642","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=7642"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/7642\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=7642"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=7642"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=7642"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}