Cos^4a+sin^2a*cos^2a/sin^2a +1=1/sin^2a

Question

Cos^4a+sin^2a*cos^2a/sin^2a +1=1/sin^2a

Answer 1

Сos²a(cos²a+sin²a)/sin²a +1=cos²a/sin²a+1=(cos²a+sin²a)/sin²a=1/sin²a
1/sin²a=1/sin²a