Can someone explain to me how to solve this homework problem?

cot(x+(pi/2) = -tanx

I have to verify it using identities. Would you start off by turning cot(x+(pi/2)) into cos(x+(pi/2))/sin(x+(pi/2))?

Question

Can someone explain to me how to solve this homework problem? 

cot(x+(pi/2) = -tanx 

I have to verify it using identities. Would you start off by turning cot(x+(pi/2)) into cos(x+(pi/2))/sin(x+(pi/2))?

anonymous · Answer

There is no real identity there… If you shift cotangent to the left pi/2, then you have tangent rotated about the x-axis (-tan(x)).