高数,求二阶导数
来源:学生作业帮 编辑:搜搜考试网作业帮 分类:数学作业 时间:2024/07/06 01:42:41
高数,求二阶导数
![](http://img.wesiedu.com/upload/e/6d/e6de8265a64b0cccf8b3509deff0a57a.jpg)
![](http://img.wesiedu.com/upload/e/6d/e6de8265a64b0cccf8b3509deff0a57a.jpg)
![高数,求二阶导数](/uploads/image/z/6155385-33-5.jpg?t=%E9%AB%98%E6%95%B0%2C%E6%B1%82%E4%BA%8C%E9%98%B6%E5%AF%BC%E6%95%B0%26nbsp%3B)
两边对x求导:
y'=e^y+xy'e^y
(1-xe^y)y'=e^y 两边对x求导:
(1-xe^y)y''+(-e^y-xy'e^y)y'=y'e^y
(1-xe^y)y''=2y'e^y+xe^y(y')^2
y''=[2y'e^y+xe^y(y')^2]/((1-xe^y)
=[2y'+x(y')^2]e^y/((1-xe^y)
=[2e^y/(1-xe^y)+x[e^y/(1-xe^y)]^2]e^y/((1-xe^y)
=[2(1-xe^y)+x][e^y]^2/((1-xe^y)^3
y'=e^y+xy'e^y
(1-xe^y)y'=e^y 两边对x求导:
(1-xe^y)y''+(-e^y-xy'e^y)y'=y'e^y
(1-xe^y)y''=2y'e^y+xe^y(y')^2
y''=[2y'e^y+xe^y(y')^2]/((1-xe^y)
=[2y'+x(y')^2]e^y/((1-xe^y)
=[2e^y/(1-xe^y)+x[e^y/(1-xe^y)]^2]e^y/((1-xe^y)
=[2(1-xe^y)+x][e^y]^2/((1-xe^y)^3