damao5517
幼苗
共回答了10个问题采纳率:90% 举报
当然是积化和差
∫sin5xsinxdx
=∫-1/2(cos6x-cos4x)dx
=-1/2∫cos6xdx+1/2∫cos4xdx
=-1/12∫cos6xd6x+1/8∫cos4xd4x
=-sin6x/12+sin4x/8
∫sin5xcosxdx
=∫1/2(sin6x+sin4x)dx
=1/2∫sin6xdx+1/2∫sin4xdx
=1/12∫sin6xd6x+1/8∫sin4xd4x
=-cos6x/12-cos4x/8
1年前
3