设<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/9ce55f7268c54c7e89e6d041cba9ae43.png?x-oss-process=image/sharpen,200"/>是<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/5bb01a0977534dcc8064f31adb69931e.png?x-oss-process=image/sharpen,200"/>的连续可微函数，且<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/3d0b17d8576a42f993efcbd690992c38.png?x-oss-process=image/sharpen,200"/><img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/cfcc2d2711354b2ca897b78fe2a2f63b.png?x-oss-process=image/sharpen,200"/>为半圆周<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/f5d4d422a9ab44d39e861350ea9e2729.png?x-oss-process=image/sharpen,200"/>起点为原点，终点为<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/931915beabf14a77823d248581c0d6f5.png?x-oss-process=image/sharpen,200"/>则<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/92184ed4ed274bcdb9cff5ef948b94ed.png?x-oss-process=image/sharpen,200"/>（）.