Second Derivatives of Parametric Equations Practice Test

If $x(t)=t^2$ and $y(t)=\sqrt{t}$ for $t>0$, what is $\dfrac{d^2y}{dx^2}$ in terms of $t$?

For $x(t)=t^3$ and $y(t)=t^2+1$, what is $\dfrac{d^2y}{dx^2}$ in terms of $t$?