Question

resolver: cot a x tan a - sen2 a/ sen a x cot a

Answer 1

Sean:
cot a = 1/tan = cos a/ sen a
cot a * tan a = 1/tan * tan a = 1
Identidad Fundamental:
sen² a+ cos² a = 1

1- sen ² a / sen a * cot a
= sen² a+ cos² a - sen ²a / sen a cot a
= cos²a / (sen a * cos a / sen a)
= cos²a/ cos a = cos a