how do I use the half-angle formula to determine the exact value of the given trigonometric expression? cot(3pi/8)

Question

anonymous · Answer

Assumming you only have half-angle formula for sin and cos.
What is cot(x) in terms of cos(x) and sin(x)?

anonymous · Answer

cosx/sinx

anonymous · Answer

What are the half angle formulae for those sin and cos?

anonymous · Answer

$$\cos(x/2)=\sqrt{(1+cosx)/2} ,  \sin(x/2)= \sqrt{(1-cosx)/2} $$

raden · Answer

the half-angle formula for sin, cos, and tan u can look here : http://www.freemathhelp.com/trig-double-angles.html also, (3pi/8) if u converting to degrees it can be 135/2 degrees