1) 3sin^2(\pi/2)-4tg^2(\pi/4)-3cos^2(\pi/6)+3ctg^2(\pi/2) 2) sin^4 \alpha +2sin^2 \alpha cos^2 \alpha +cos^4 \alpha 3) cosx×ctg

Question

4 года назад

5

1) 3sin^2(\pi/2)-4tg^2(\pi/4)-3cos^2(\pi/6)+3ctg^2(\pi/2) 2) sin^4 \alpha +2sin^2 \alpha cos^2 \alpha +cos^4 \alpha 3) cosx×ctg

1) 3sin^2(\pi/2)-4tg^2(\pi/4)-3cos^2(\pi/6)+3ctg^2(\pi/2)
2) sin^4 \alpha +2sin^2 \alpha cos^2 \alpha +cos^4 \alpha
3) cosx×ctgx-ctgx-sinx=0

Знания

Математика

1 ответ:

Iolisa [14] · Answer 1 · 2020-07-04T16:21:57+03:00

1.=3*1-4*1-3*3/4=3-4-0.75=-1-0.75=-1.75.
2. sin^4 \alpha +2sin^2 \alpha cos^2 \alpha +cos^4 \alpha =
( sin^2 \alpha + cos^2 \alpha) ^2 =1
3. cosx×ctgx-ctgx-sinx= cosx×cosx/sinx- cosx/sinx - sinx=
cos^2x /sinx- cosx/sinx - sinx =
(cos^2x - cosxsinx - sin^2x)/ sinx=0,
(cos2x -0,5 sin2x)/ sinx=0, cos2x -0,5 sin2x =0
cos2x =0,5 sin2x , 0,5tg2x=1,tg2x=2 2x=argtg2+пn,
x=0,5 argtg2+пn,где целое число.