求证：2(sin2a+1)/(1+sin2a+cos2a)=tana+1
问题描述：
求证：2(sin2a+1)/(1+sin2a+cos2a)=tana+1
答
2(sin2a+1)/(1+sin2a+cos2a)
=2（2sinacosa+sin^2 a+cos^2 a)/(1+2sinacosa+2cos^2 a-1)
=2(sina+cosa)^2/2cosa(sina+cosa)
=(sina+cosa)/cosa
=tana+1
答
sin2a=2sinacosa 1=(sina)^2+(cosa)^22(sin2a+1)=2(sina+cosa)^21+sina2a+cos2a=1+2sinacosa+2(cosa)^2-1=2cosa(sina+cosa)2(sin2a+1)/(1+sin2a+cos2a)=[2(sina+cosa)^2]/[2cosa(sina+cosa)]=(sina+cosa)/cosa=tana+...