关于三角函数求不定积分的问题

$sinxcosx/(sinx+cosx)dx请数学牛人帮帮忙!

∫(sinxcosx)/(sinx+cosx)dx

=∫(2sinxcosx)/[2√2sin(x+π/4)]dx

=∫sin2x/[2√2sin(x+π/4)]dx

=∫-cos(2x+π/2)/[2√2sin(x+π/4)]dx

=∫[2sin^2(x+π/4)-1]/[2√2sin(x+π/4)]dx

=∫{√2/2*sin(x+π/4)+√2/4[-1/sin(x+π/4)]}dx

=∫√2/2*sin(x+π/4)dx+∫√2/4[-1/sin(x+π/4)]dx

=-√2/2*cos(x+π/4)+√2/4*cos(x+π/4)/sin(x+π/4)+C
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