∫sin 2\3 xdx,∫e^sinx cosxdx,∫1\x^2 sin 1\x dx求不定积分
问题描述：
∫sin 2\3 xdx,∫e^sinx cosxdx,∫1\x^2 sin 1\x dx求不定积分
答
∫ sin(2x/3) dx
= (3/2)∫ sin(2x/3) d(2x/3)
= (-3/2)cos(2x/3) + c
∫ e^sinx * cosx dx
= ∫ e^sinx dsinx
= e^sinx + c
∫ 1/x² * sin(1/x) dx
= ∫ sin(1/x) d(-1/x)
= -[-cos(1/x)] + c
= cos(1/x) + c