∫[ (sinx * cosx)/(1+(sinx)^4)]/dx
问题描述：
∫[ (sinx * cosx)/(1+(sinx)^4)]/dx
答
(1/2)|sin2xdx/{1+[(sinx)^2]^2}=(1/4)|d(cos2x)/{1+(1-cos2x)/2}
=-(1/2)|d[1+(1-cos2x)/2]/{1+(1-cos2x)/2}
=-(1/2)ln|1+(1-cos2x)/2|+C