x=t^2/2=0.5(1-y)^2(1-y)² = 2x-2y'(1-y) = 2y'(y-1) = 1 y' = 1/(y-1)y''(y-1)+y'y' = 0y'' = y'y'/(1-y) = 1/(1-y)³
dy/dx=[dy/dt]/[dx/dt]=-1/td^2y/dx^2=d[-1/t]/dx=(d[-1/t]/dt)(1/[dx/dt])=[1/t^2]*[1/t]=1/t^3
游客1
x=t^2/2=0.5(1-y)^2
(1-y)² = 2x
-2y'(1-y) = 2
y'(y-1) = 1 y' = 1/(y-1)
y''(y-1)+y'y' = 0
y'' = y'y'/(1-y)
= 1/(1-y)³
游客2
dy/dx=[dy/dt]/[dx/dt]=-1/t
d^2y/dx^2=d[-1/t]/dx=(d[-1/t]/dt)(1/[dx/dt])=[1/t^2]*[1/t]=1/t^3