1) 1-sin^4x-5cos^4x=0

2) 4sin^3x - (sinx+cosx) = 0

2) 4sin^3x - (sinx+cosx) = 0

4sin^3 x - sinx - cosx = 0

(4sin^3 x - sinx) - cosx = 0

4sin x * (sin^2 x - 1) - cosx = 0

-4sin x * (1 - sin^2 x) + cosx = 0

-4sin x * cos^2 x + cosx = 0

cos x * (1 - 4sin x*cos x) = 0

Или cos x = 0 = >

x = п/2+2 пn

Или 1 - 4sin x*cos x = 0 = >

1 - 4*1/2 * (sin 0 + sin 2x) = 0

1 - 2sin 2x = 0

sin 2x = 1/2

2x = п/6 = >

x = п/12 + 2 пn