2sinx-sin2x的差除以2sinx+sin2x化简

题目

2sinx-sin2x的差除以2sinx+sin2x化简

答案

(2sinX-sin2X)/(2sinX+sin2X)
=(2-2cosx)/(2+2cosx)
=(1-cosx)/(1+cosx)
=[(1-cosx)/2]/[(1+cosx)/2]
=sin^2(x/2)/cos^2(x/2)
=tan^2(x/2)