Tolong bantu kak.! nomor 9 A - D . Sederhanakan bentuk persamaan berikut.!

a.
cosx. cosec x. tanx
cosx. 1/sinx. sinx/cosx
1

b.
cosx. cotx + sinx
cosx. cosx/sinx + sinx
cos²x / sinx + sinx
cos²x + sin²x / sinx
1 / sinx
cosecx

c.
sinx / 1+cosx + sinx /1-cosx

sinx(1-cosx) + sinx(1+cosx)/ 1-cos²x
sinx(1-cosx + 1+cosx) / sin²x
(1-cosx+1+cosx) / sinx
0/sinx
0

D.
(sina + cosa)²+(sina-cosa)²
(sin²a+2sinacosa+cos²a) + (sin²a-2sinacosa+cos²a)
1 + 1
2

a) cos x . cosec x . tan x
= cos x . 1/(sin x) . (sin x)/(cos x)
= 1

b) cos x . cot x + sin x
= cos x . (cos x)/(sin x) + sin x
= (cos^2 x + sin^2 x)/(sin x)
= 1/(sin x)
= cosec x

c) (sin x)/(1 + cos x) + (sin x)/(1 - cos x)
= (sin x(1 - cos x) + sin x(1 + cos x)) / (1 + cos x)(1 - cos x)
= (sin x - sin x cos x + sin x + sin x cos x) / (1 - cos^2 x)
= (2 sin x) / (sin^2 x)
= 2/(sin x)
= 2 cosec x

d) (sin a + cos a)^2 + (sin a - cos a)^2
= sin^2 a + 2 sin a cos a + cos^2 a + sin^2 a - 2 sin a cos a + cos^2 a
= 2 sin^2 a + 2 cos^2 a
= 2(sin^2 a + cos^2 a)
= 2(1)
= 2