1/sinA-cosA*ctgA=sinA

Question

1/sinA-cosA*ctgA=sinA

Answer 1

CtgA = cosA/sinA
1/sinA-cosA*cosA/sinA-sinA=0
1/sinA-cosA^2/sinA-sinA=0
(1-cosA^2)/sinA=sinA
sinA=корень из 1-cosA^2
sinA/sinA - sinA = 0
1-sinA=0
sinA=1