∫arccosxdx=?
解：∫arccosxdx =xarccosx-∫xd(arccosx) =xarccosx+∫xdx/√(1-x²) =xarccosx+(1/2)∫d(1-x²)/√(1-x²) =xarccosx+(1/2)∫[(1-x²)^(-1/2)]d(1-x²) =xarccosx+√(1-x²)+C