Question

Verify if this is an identity cot(-x) tanx=-1

Answer 1

hello :
cot(-x) tan(x)=-1......(*)
* cot(x) = 1/tan(x)
 cot(-x) = -cot(x)= -(1/tan(x))

                       cot(-x) tan(x) =   -(1/tan(x))×tan(x)=-1