Second Derivatives of Parametric Equations Practice Test

For which interval of $$t$$ is the curve given by the parametric equations $$x(t) = e^t$$ and $$y(t) = t^3 - 3t$$ concave up?

A curve is defined by the parametric equations $$x(t) = e^t$$ and $$y(t) = \ln(t+1)$$ for $$t > -1$$. What is the value of $$\frac{d^2y}{dx^2}$$ at $$t=1$$?