When defining a plain standard distributed stochastic variable X, and can find the probability of X <= 0.6 using the Probability function, but how can I get the value for a certain probability, as is done with the fsolve function for example below.

However, the fsolve used to defined Prev above appears to be a bad way to do it, since the Prev function can't for example plot.

Is there some build in way of doing reverse of Probability for a stocastical variable ?

Doing the following:

Why is int used when defining F not evaluated to x^2/2 when used to defined function F as shown in (2), when the int is evaluated when used separately in (3)?