来源:学生作业帮 编辑:神马作文网作业帮 分类:数学作业 时间:2024/11/13 00:38:26
求下列曲线弧长(要详细计算步骤谢谢)
dx/dy=y/2-1/(2y)
ds=√1+[y/2-1/(2y)]²dy
=√【1+(y/2)²-1/2+(1/2y)²】dy
=√[(y/2)²+1/2+(1/2y)²]dy
=[y/2+1/(2y)]dy
所以
弧长=∫ds=∫(1,e)[y/2+1/(2y)]dy
=[y²/4+1/2lny](1,e)
=e²/4+1/2-1/4
=(e²+1)/4