证明TANα/2=±√1-COSα/1+COSα,

问题描述:

证明TANα/2=±√1-COSα/1+COSα,

√(1-COSα)/(1+COSα)=√[1-(1-2*(sina/2)^2]/[1+2*(COSα/2)^2-1]
=√2*(sinα/2)^2/2*(COSα/2)^2=√tanα^2=±tanα/2