sin^2a+sin^2b-sin^2a * sin^2b+cos^2a * cos^2b 化简
问题描述：
sin^2a+sin^2b-sin^2a * sin^2b+cos^2a * cos^2b 化简
答
原式=sin^2a(1-sin^2b)+sin^2b+cos^2a*(1-sin^2b)=(1-sin^2b)(sin^2a+cos^2a)+sin^2b=cos^2b+sin^2b=1
答
=1
答
结果是1(sina)^2+(sinb)^2-(sina)^2*(sinb)^2+(cosa)^2*(cosb)^2=(sina)^2*(1-sinb^2)+(sinb)^2+(cosa)^2*(cosb)^2=sina^2*cosb^2+cosa^2*cosb^2+sinb^2=(sina^2+cosa^2)*cosb^2+sinb^2=cosb^2+sinb^2=1
答
1
sin^2a(1-sin^2b)+sin^2b+cos^2acos^b
=sin^2a*cos^2b+sin^2b+cos^2acos^2b
=cos^2b*(sin^2a+cos^2a)+sin^2b
=cos^2b+sin^2b
=1