∫(0->π) √(1-sinx) dx
=∫(0->π) √(sin^2 x/2 +cos^2 x/2 -2sinx/2 * cosx/2) dx
=∫(0->π) √(sinx/2 -cosx/2)^2 dx
∵0<=x<=π
∴0<=x/2<=π/2
当0<=x/2<=π/4时
cosx/2>sinx/2
当π/4<=x/2<=π/2时
cosx/2
=∫(0->π/2) cosx/2dx-∫(0->π/2) sinx/2 dx +∫(π/2->π) sinx/2 dx -∫(π/2->π) cosx/2 dx
=2 sinx/2|(0->π/2) +2cosx/2|(0->π/2) -2cosx/2|(π/2->π) -2sinx/2|(π/2->π)
=2(√2/2 -0) +2(√2/2 -1) -2(0-√2/2) -2(1-√2/2)
=√2 +√2-2 +√2 -2+√2
=4√2-4
你是电气几班