Using the Leibniz integral rule to prove smoothness of the function.

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I am working with thee probability density function that depends on non-deterministic ($v$) and random ($x$) parameters (and random parameters depend on non-det parameters):

$Pr(v)=\int_{G(v)} dP(v)$,

where $G (v)$ is the "goal" region, the probability of getting into it must be determined and that, in turn, depends on $v$ and $x$.

We consider the normal distribution function $P(v)=N(0,v)$:

$Pr(v)=\frac{1}{\sqrt{2\pi v}}\int_{g(v)}^{m(v)} e^{-\frac{(x)^2}{2v}}dx$

So that by replacing $a=\frac{1}{\sqrt{2\pi v}}$ and $f(x,v)=e^{-\frac{(x)^2}{2v}}$ we have:

$Pr(v)=a\int_{g(v)}^{m(v)} f(v,x)dx$

We also assume that f,g, and m are smooth functions.

Using Leibniz integral rule we can rewrite the derivative of the integral as:

$\frac{d}{dv}(a\int_{g(v)}^{m(v)} f(v,x)dx)=a(f(v,m(v))\frac{d}{dv}m(v)-f(v,g(v))\frac{d}{dv}g(v)+\int_{g(v)}^{m(v)} \frac{d}{dv}f(v,x)dx)$

From our assumptions, we can conclude that $f(v,m(v))\frac{d}{dv}m(v)-f(v,g(v))\frac{d}{dv}g(v)$ part is smooth by definition of the smooth functions.

So the only term we care is $\int_{g(v)}^{m(v)} \frac{d}{dv}f(v,x)dx$, which is also should be smooth.

NOTE that we can use any assumptions to prove that function $Pr(v)$ is smooth.

MY QUESTION IS: Can somebody help me to finish the proof?

I will really appreciate your help!