化简cotx/2 - tanx/2

问题描述:

化简cotx/2 - tanx/2

cosx/2 / sinx/2 - sinx/2 / cosx/2
=(cos^2(x/2) - sin^2(x/2))/(sinx/2.cos/2)
=cosx/((1/2)sinx)
=2cotx