标题很长很长很长长长长长长长长长~
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:2024/09/20 11:47:56
标题很长很长很长长长长长长长长长~
如图
如图
是这样的
d^2/dx^2=[d(dy/dx)]/dx
因为dy/dx=y'(t)/x'(t)
所以
d^2/dx^2
=[d(y'(t)/x'(x))]/dx
={[d(y'(t)/x'(x))]/dt}*dt/dx
={[d(y'(t)/x'(x))]/dt}*(1/x'(t))
={[y''(t)x'(t)-y'(t)x''(t)]/[x'(t)^2]}/x'(t)
=[y''(t)x'(t)-y'(t)x''(t)]/[x'(t)^3]
关键在于
[d(y'(t)/x'(x))]/dx={[d(y'(t)/x'(x))]/dt}*dt/dx
这一步.
d^2/dx^2=[d(dy/dx)]/dx
因为dy/dx=y'(t)/x'(t)
所以
d^2/dx^2
=[d(y'(t)/x'(x))]/dx
={[d(y'(t)/x'(x))]/dt}*dt/dx
={[d(y'(t)/x'(x))]/dt}*(1/x'(t))
={[y''(t)x'(t)-y'(t)x''(t)]/[x'(t)^2]}/x'(t)
=[y''(t)x'(t)-y'(t)x''(t)]/[x'(t)^3]
关键在于
[d(y'(t)/x'(x))]/dx={[d(y'(t)/x'(x))]/dt}*dt/dx
这一步.