3) 2/5 * 6/13 + 1/4 * 6/13 4) 3 3/4 * 2/5 - 3 6/25 * 5/27 5) 3/5 - 3/5 * 2/7 6) 1/7 * 1/8 + 1/7 * 1/6 - id1034305420220109 от Як12 09.01.2022 05:22

Question

Математика: 3) 2/5 * 6/13 + 1/4 * 6/13 4) 3 3/4 * 2/5 - 3 6/25 * 5/27 5) 3/5 - 3/5 * 2/7 6) 1/7 * 1/8 + 1/7 * 1/6

Як12 · Accepted Answer

1. sinα+cosα=6/5
(sinα+cosα)²=(6/5)²
sin²α+2sinα*cosα+cos²α=36/25
1+2sinαcosα=36/25. 2sinα*cosα=36/25-1. 2sinα*cosα=11/25
sinα*cosα=11/50

2. sinα+cosα=1/2
tgα+ctgα=sinα/cosα+cosα/sinα=(sin²α+cos²α)/(sinα*cosα)=1/(sinα*cosα)

sinα+cosα=1/2. (sinα+cosα)²=(1/2)². sin²α+2sinα*cosα+cos²α=1/4
1+2sinα*cosα=1/4. 2sinα*cosα=-3/4. sinα*cosα=-3/8
1:(-3/8)=-8/3
tgα+ctgα=-8/3

3. tgα=2/5. sinα/cosα=2/5. sinα=2cosα/5

(sinα+2cosα)/(cosα-3sinα)=(2cosα/5+2cosα)/(cosα-6cosα/5)=
=[cosα*(2/5+2)] / [cosα*(1-6/5)]=(12/5):(-1/5)=-12
(sinα+2cosα)/(cosα-3sinα)=-12

3) 2/5 * 6/13 + 1/4 * 6/13 4) 3 3/4 * 2/5 - 3 6/25 * 5/27 5) 3/5 - 3/5 * 2/7 6) 1/7 * 1/8 + 1/7 * 1/6

MOGZ ответил

3) 2/5 * 6/13 + 1/4 * 6/13
4) 3 3/4 * 2/5 - 3 6/25 * 5/27
5) 3/5 - 3/5 * 2/7
6) 1/7 * 1/8 + 1/7 * 1/6