## 165 Reputation

1 years, 265 days

## partial derivatives...

@Carl Love

Thank you.

How would I specify the differentiating variable if the function is of multiple variables?

## @acer That's what I meant. Than...

@acer That's what I meant. Thank you.

## @mmcdara Thank you but this is much...

@mmcdara Thank you but this is much more than what I need.

I just want functions that are not positive everywhere (in other words I want to discard expressions that are positive everywhere).

## @Rouben Rostamian  Thank you. This ...

@Rouben Rostamian  Thank you. This is perfect.

## Works...

@sand15  Thank you so much!

## @Carl Love This is very nice. I wis...

This is very nice. I wish it were easier to do.

I have an additional question now. Would it be possible to animate this if there was another constant present (say for values of k from -1 to 1

(1+k)/(r^2*sin(theta)^2)

## @sand15  sorry I should have made ...

@sand15

sorry I should have made that clear r>0 and theta goes from -Pi to Pi. And want some sort of animation/plot that makes it easy to visualize where the function is greater than zero.

## @Carl Love  I see this now, Thanks....

@Carl Love  I see this now, Thanks.

## @mmcdara Hi thank you.But I already...

Hi thank you.

But I already know how to solve this pde manually. I wanted to practice my hand at doing this via maple.

## We definitely need benchmarking....

I think having a benchmarking suite would be extremely helpful.

## @C_R This is it. Thanks ...

This is it. Thanks

## @ecterrab I started with the differ...

@ecterrab I started with the differential geometry package and a lot of my scripts are written with the differential geometry package. I have been slowly moving towards the physics package.
Also exterior calculus seems to be a bit simpler in the differential geometry package. For example wedge products dont seem to have a simple equivalent in the physics package.

## @acer I use the physics and differe...

@acer I use the physics and differential geometry package. with physics package Petrov and Segre classification, calculation of the Riemann, Ricci and Einstein Tensor.
With Differential Geometry package Most of the time I calculate covariant derivatives, exterior derivatives.

With both packages a lot of my work involves using pdsolve to solve sets of equations and maple is very good at it.

Recently I have been wondering if getting better specs might significantly help with my work and hence my question.

## @ecterrab  I think the post is aski...

@ecterrab  I think the post is asking why the Stress Energy tensor is nonzero for a vacuum solution.

## @mmcdara  The only simplification t...

@mmcdara  The only simplification tools I was aware of was simplify and subs.