I'm practicing statistics and I'm wondered how one can solve the following problem from Sage:
Find a numerical value of $x$ such that $\frac{1}{\sqrt{2\pi}}\int_{-\infty}^x e^{-t^2/2}dt=0.987654321$. I was thinking to different solutions:
1) Is there an inverse of normal distribution cumulative function?
2) Can we write it as $f'(x)=e^{-x^2/2},f(0)=1/2,f(x_0)=0.987654321$ and use some numerical method to solve the differential equation?
but I don't know are those functions implemented in Sage.
