Question

Решите пж
1)1-2 sin⁡(π/4+x/5)=0
2)5cos^2x + sin^2x + 6sin⁡x∙cos⁡x=0

Answer 1

sin2x-3x(2cosxsinx)5cos2x =0

sin2x-3sin2x+5cos2x=0

5cos2x-2sin2x=0:cos2x

5-2tgx=0

2tgc=5

tgx=2.5

x=arctg2,5