In terms of the tangent of a positive acute angle, what is the expression for tan13π/18?

Question

I have two questions please!! Its due in 1 hour and a half.

In terms of the cotangent of a positive acute angle, what is the expression for cot17π9?

In terms of the tangent of a positive acute angle, what is the expression for tan13π/18?

Answer 1

Look at a unit circle.

cot 17π / 9 is in QIV, frefence angle is π / 9. cot 17π / 9 = - cot π / 9

Do the same for 13π / 18