## 150 Reputation

11 years, 201 days

## How to tell Maple not to expand derivati...

Maple 16

I'm simplifying this Reynolds Equation starting from here:

Reynolds:=Diff(p(x)*h(x)^3/(12*mu)*Diff(p(x),x),x)-u(x)/2*Diff(p(x)*h(x),x)+Diff(p(x)*h(x)^3/(12*mu)*Diff(p(x),z),z)=Diff(p(x)*h(x),t):

Then I apply the dchange command:

dchange({p(x)=P(X)*Pa,x=Lx*X,h(x)=H(X)*h2},Reynolds,{P,h,X,u,H});

The problem is that it expands the new derivatives and I need the equation in its compact form.

How do I tel Maple only to make the substitution but not to expand the result?

I know that it expands by default, can I modify that?

## Student-T Inverse...

I need to integrate the Student-T function which is a function of two variables (nu and t). Maple allows me to use this function through this command:

with(Statistics);

PDF(RandomVariable(StudentT(nu)),t);

The integration of this function gives me the probability (p) of certain event (nu is already known):

p=Int(Student,t=-infinity..X)

If I provide the value of X I can compute the integral easily, now the problem appears when I want to...

## Fraction Display...

Maple

This is a simple question,

How do I tell maple to give only one fraction instead of a sum of several with different denominators.

Example

if i sum 1/3 + x/5 maple simply gives me: 1/3 + x/5

I want maple to give me (5+3x)/15

Thanks

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