∫(0→1) dx ∫(x→1) (siny)/y dy,交换积分次序= ∫(0→1) (siny)/y dy ∫(0→y) dx= ∫(0→1) (siny)/y · y dy= ∫(0→1) siny dy= - cosy：[0→1]= - (cos(1) - cos(0))= 1 - cos(1)