What is the number of solutions of the equation cot2x cot3x = 1 for 0 < x

What is the general solution of cos¹⁰⁰ x - sin¹⁰⁰ x = 1?

In a triangle ABC tan A + tan B + tan C = k  What is the value of cot A cot B cot C? 

What is sin12° sin48° equal to?