Question

решите уравнение  2(1+ctg^2x)(cos^2x-sin^2x)=1/sin^2x

Answer 1

2* 1/sin²x *cos2x-1/sin²x=0
1/sin²x *(2cos2x-1)=0
2cos2x-1=0, sinx≠0
cos2x=1/2⇒2x=+-π/3+2πn⇒x=+-π/6+πn