Sau khi \u0111\u1ec1 To\u00e1n THPT qu\u1ed1c gia 2018 b\u1ecb nh\u1eadn x\u00e9t qu\u00e1 kh\u00f3, v\u01b0\u1ee3t s\u1ee9c th\u00ed sinh, m\u1ed9t c\u00e2u h\u1ecfi \u0111\u01b0\u1ee3c cho l\u00e0 kh\u00f4ng ch\u1eb7t ch\u1ebd v\u1ec1 m\u1eb7t t\u1eeb ng\u1eef v\u00e0 \u0111i\u1ec1u ki\u1ec7n b\u00e0i to\u00e1n, n\u00ean kh\u00f4ng c\u00f3 \u0111\u00e1p \u00e1n ch\u00ednh x\u00e1c.<\/p>\n

C\u00e2u h\u1ecfi ch\u01b0a ch\u1eb7t ch\u1ebd<\/h3>\n

C\u1ee5 th\u1ec3, c\u00e2u 16 m\u00e3 \u0111\u1ec1 109: M\u1ed9t ng\u01b0\u1eddi g\u1eedi ti\u1ebft ki\u1ec7m v\u00e0o ng\u00e2n h\u00e0ng v\u1edbi l\u00e3i su\u1ea5t 7,5%\/n\u0103m. Bi\u1ebft r\u1eb1ng n\u1ebfu kh\u00f4ng r\u00fat ti\u1ec1n ra kh\u1ecfi ng\u00e2n h\u00e0ng th\u00ec c\u1ee9 sau m\u1ed7i n\u0103m s\u1ed1 ti\u1ec1n l\u00e3i s\u1ebd \u0111\u01b0\u1ee3c nh\u1eadp v\u00e0o v\u1ed1n \u0111\u1ec3 t\u00ednh l\u00e3i cho n\u0103m ti\u1ebfp theo. H\u1ecfi sau \u00edt nh\u1ea5t bao nhi\u00eau n\u0103m ng\u01b0\u1eddi \u0111\u00f3 thu \u0111\u01b0\u1ee3c (c\u1ea3 s\u1ed1 ti\u1ec1n g\u1eedi ban \u0111\u1ea7u v\u00e0 l\u00e3i) g\u1ea5p \u0111\u00f4i s\u1ed1 ti\u1ec1n g\u1eedi ban \u0111\u1ea7u, gi\u1ea3 \u0111\u1ecbnh trong kho\u1ea3ng th\u1eddi gian n\u00e0y l\u00e3i su\u1ea5t kh\u00f4ng thay \u0111\u1ed5i v\u00e0 ng\u01b0\u1eddi \u0111\u00f3 kh\u00f4ng r\u00fat ti\u1ec1n ra?<\/p>\n

B\u1ed1n ph\u01b0\u01a1ng \u00e1n tr\u1ea3 l\u1eddi l\u00e0: A 12 n\u0103m; B 10 n\u0103m; C 9 n\u0103m; D 11 n\u0103m.<\/p>\n

H\u1ed3 Phi Kh\u00e1nh, th\u1ee7 khoa 30 \u0111i\u1ec3m n\u0103m 2017, gi\u1ea3i b\u00e0i n\u00e0y nh\u01b0 sau:<\/p>\n

G\u1ecdi A l\u00e0 s\u1ed1 ti\u1ec1n g\u1eedi ban \u0111\u1ea7u, n l\u00e0 s\u1ed1 n\u0103m g\u1eedi. Theo b\u00e0i ra: Sau 1 n\u0103m, s\u1ed1 ti\u1ec1n c\u1ea3 v\u1ed1n l\u1eabn l\u00e3i l\u00e0 A + A. 7,5% =A. 1,075.<\/p>\n

Sau 2 n\u0103m, s\u1ed1 ti\u1ec1n c\u1ea3 v\u1ed1n l\u1eabn l\u00e3i l\u00e0: A.1,075 + A. 1,075.7,5% = A. 1,075^2.<\/p>\n

Sau n n\u0103m, s\u1ed1 ti\u1ec1n c\u1ea3 v\u1ed1n l\u1eabn l\u00e3i l\u00e0 A. 1,075^n.<\/p>\n

S\u1ed1 ti\u1ec1n n\u00e0y b\u1eb1ng 2 l\u1ea7n ban \u0111\u1ea7u n\u00ean: A. 1,075^n = 2A –> n=log_1,075 (2) ~ 9,58.<\/p>\n

Kh\u00e1nh cho hay \u0111\u1ec1 To\u00e1n kh\u00f4ng kh\u00f3, theo c\u00e1ch hi\u1ec3u th\u00f4ng th\u01b0\u1eddng c\u1ee7a \u0111\u1ec1 b\u00e0i s\u1ebd t\u00ecm ra \u0111\u00e1p \u00e1n l\u00e0 10 n\u0103m. Tuy nhi\u00ean, n\u1ebfu suy t\u1edbi c\u00f9ng ch\u1eb7t ch\u1ebd v\u1ec1 m\u1eb7t c\u00e2u ch\u1eef th\u00ec \u0111\u1ec1 b\u00e0i kh\u00f4ng c\u00f3 \u0111\u00e1p \u00e1n \u0111\u00fang. V\u00ec v\u1eady, \u00fd ki\u1ebfn nh\u1eadn \u0111\u1ecbnh \u0111\u1ec1 ch\u01b0a chu\u1ea9n l\u00e0 h\u1ee3p l\u00fd.<\/p>\n

Theo TS Tr\u1ea7n Nam D\u0169ng – \u00a0\u0110H Khoa h\u1ecdc T\u1ef1 nhi\u00ean (\u0110H Qu\u1ed1c gia TP.HCM) – “mu\u1ed1n ra \u0111\u00fang b\u1eb1ng g\u1ea5p \u0111\u00f4i th\u00ec \u0111\u00e1p s\u1ed1 ph\u1ea3i l\u00e0 s\u1ed1 l\u1ebb. N\u1ebfu ch\u1eb5n n\u0103m th\u00ec s\u1ebd ph\u1ea3i l\u1edbn h\u01a1n g\u1ea5p \u0111\u00f4i m\u1ed9t ch\u00fat. T\u1ea5t nhi\u00ean c\u00f3 th\u1ec3 \u0111\u1eb7t c\u00e2u h\u1ecfi ch\u00ednh x\u00e1c h\u01a1n”.<\/p>\n

Theo th\u1ea7y Tr\u1ea7n Tr\u00e0 H\u01b0\u01a1ng, gi\u00e1o vi\u00ean luy\u1ec7n thi m\u00f4n To\u00e1n t\u1ea1i TP.HCM, “b\u00e0i to\u00e1n n\u00e0y kh\u00f4ng c\u00f3 \u0111\u00e1p \u00e1n \u0111\u00fang, ra \u0111\u1ec1 thi nh\u01b0 v\u1eady kh\u00f4ng \u1ed5n”.<\/p>\n

Th\u1ea7y Tr\u1ea7n Minh Th\u1ecbnh, T\u1ed5 tr\u01b0\u1edfng T\u1ed5 To\u00e1n tr\u01b0\u1eddng THPT B\u00f9i Th\u1ecb Xu\u00e2n (TP.HCM), n\u00eau quan \u0111i\u1ec3m c\u00e2u h\u1ecfi kh\u00f4ng h\u1eb3n \u0111\u00e3 sai nh\u01b0ng t\u1eeb ng\u1eef kh\u00f4ng chu\u1ea9n. N\u1ebfu theo y\u00eau c\u1ea7u c\u1ee7a b\u00e0i to\u00e1n, kh\u00f4ng c\u00f3 s\u1ed1 nguy\u00ean n\u00e0o \u0111\u00fang.<\/p>\n

“Tuy nhi\u00ean,\u00a0h\u1ecdc sinh<\/a>\u00a0\u0111\u00e3 quen v\u1edbi d\u1ea1ng to\u00e1n n\u00e0y, c\u00e1c em v\u1eabn c\u00f3 th\u1ec3 ch\u1ecdn 10 n\u0103m – \u0111\u00e1p \u00e1n \u0111\u00fang theo B\u1ed9 GD&\u0110T, n\u00ean s\u1ebd kh\u00f4ng m\u1ea5t \u0111i\u1ec3m, d\u00f9 c\u00e2u h\u1ecfi kh\u00f4ng th\u1eadt chu\u1ea9n x\u00e1c”, th\u1ea7y Th\u1ecbnh n\u00eau quan \u0111i\u1ec3m.<\/p>\n

Trong khi \u0111\u00f3, th\u1ea7y Nguy\u1ec5n Cao Tr\u1ecdng, gi\u00e1o vi\u00ean trung t\u00e2m luy\u1ec7n thi cao h\u1ecdc, cho r\u1eb1ng c\u00e1ch ra \u0111\u1ec1 \u1edf c\u00e2u tr\u00ean ch\u01b0a \u0111\u00fang. C\u00e2u h\u1ecfi ch\u00ednh x\u00e1c ph\u1ea3i l\u00e0 “\u00edt nh\u1ea5t bao nhi\u00eau n\u0103m th\u00ec c\u00f3 th\u1ec3 g\u1ea5p \u0111\u00f4i” m\u1edbi \u0111\u00fang.<\/p>\n

Th\u1ea7y gi\u00e1o n\u00e0y c\u0169ng nh\u1eadn \u0111\u1ecbnh c\u00e1ch h\u1ecfi c\u1ee7a \u0111\u1ec1 sai nh\u01b0ng kh\u00f4ng \u1ea3nh h\u01b0\u1edfng nhi\u1ec1u \u0111\u1ebfn vi\u1ec7c l\u00e0m b\u00e0i c\u1ee7a th\u00ed sinh.<\/p>\n

“H\u1ecdc sinh kh\u00e1 v\u1eabn c\u00f3 th\u1ec3 hi\u1ec3u \u00fd \u0111\u1ec1 m\u00e0 ch\u1ecdn \u0111\u00e1p \u00e1n 10 n\u0103m, c\u00f2n h\u1ecdc sinh y\u1ebfu th\u00ec kh\u00f4ng th\u1ec3 c\u00f3 c\u00f4ng th\u1ee9c \u0111\u1ec3 l\u00e0m b\u00e0i n\u00e0y”, th\u1ea7y Tr\u1ecdng n\u00f3i.<\/p>\n

B\u1ea1n \u0110inh Quang C\u01b0\u1eddng, CLB Th\u1ee7 khoa Vi\u1ec7t Nam, cho hay \u0111\u00e2y l\u00e0 d\u1ea1ng b\u00e0i h\u1ecdc sinh g\u1eb7p nhi\u1ec1u. C\u00f3 th\u1ec3 th\u00ed sinh v\u1eabn hi\u1ec3u \u0111\u1ec1 nh\u01b0ng To\u00e1n h\u1ecdc ph\u1ea3i ch\u00ednh x\u00e1c v\u1ec1 c\u00e2u ch\u1eef. N\u1ebfu th\u00ed sinh ph\u1ea3n \u0111\u1ed1i c\u00e2u h\u1ecfi n\u00e0y tr\u00ean di\u1ec7n r\u1ed9ng, B\u1ed9 GD& \u0110T n\u00ean xem x\u00e9t l\u1ea1i.<\/p>\n

Ngu\u1ed3n: Zing.vn<\/em><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

M\u1ed9t c\u00e2u h\u1ecfi trong \u0111\u1ec1 thi m\u00f4n To\u00e1n THPT qu\u1ed1c gia 2018 \u0111\u01b0\u1ee3c cho l\u00e0 kh\u00f4ng c\u00f3 l\u1ef1a ch\u1ecdn ch\u00ednh x\u00e1c trong s\u1ed1 4 \u0111\u00e1p \u00e1n \u0111\u01b0\u1ee3c \u0111\u01b0a ra. Sau khi \u0111\u1ec1 To\u00e1n THPT qu\u1ed1c gia 2018 b\u1ecb nh\u1eadn x\u00e9t qu\u00e1 kh\u00f3, v\u01b0\u1ee3t s\u1ee9c th\u00ed sinh, m\u1ed9t c\u00e2u h\u1ecfi \u0111\u01b0\u1ee3c cho l\u00e0 kh\u00f4ng ch\u1eb7t ch\u1ebd […]<\/p>\n","protected":false},"author":1,"featured_media":32242,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"tdm_status":"","tdm_grid_status":""},"categories":[19],"tags":[],"yoast_head":"\n