Statement Justification
cot²(x/2) Given
1/tan²(x/2) cotx=1/tanx
1/(√1-cosx/1+cosx)² ♦
1/1-cosx/1+cosx Simplify
♣/◼ Multiplicative inverse

This proof shows the first five steps for verifying
cot²(x/y) = cosx+1/cosx-1

♦ :
♣ :
◼ :