求下列式子的不定积分一、（1-x）／（9-4x^2)dx二、(1／x^2)sin(1／x)dx三、sin2xcos3xd

手机没有积分号,就拿“$”代替了
一、 $(1-x)/(9-4x^2)dx
=$1/[3^2 -(2x)^2]dx - $x/(9-4x^2)dx
=(1/6)ln[(3+x)/(3-x)] + (1/8)ln(9-4x^2) + c
二、$sin(1/x)/x^2dx
= -$sin(1/x)d(1/x)
= cos(1/x) + c
三、$sin2x cos3x dx
= 0.5$(sin5x - sinx) dx
= ($sin5xdx - $sinxdx)/2
=(-0.2cos5x - cosx)/2 + c