@Carl Love 

It worked great! Thank you very much!

@acer 

Amazing! Thank you again!

@acer 

Thank you for your attention! I think my question was not clear!

@dharr 

You saved my life! Thank you very much! Could I do another question? How could I plot multiple plots on the same graph for different values of m?

@ecterrab 

Thank you!

@ecterrab 

Maybe I didn't make myself clear. I would like to know, how or if it is possible to make the internal product between a Killing vector of a certain space-time, Schwarzschild for example, with a scalar, vector or tensor. When I call the KillingVector command, I get a list of vectors. How can I use one of these vectors, transform it into an Array to be able to make an internal product with a scalar, vector or tensor? In the Physics package, the Killing vectors appear to be blocked, as I can't do any algebraic operations on them. I would like to make an internal product as shown in the image below.

@ecterrab 

Good! I need to do a calculation like eq. (7), if possible with index summation, because it's more elegant. I attached the file again.

test.mw

@ecterrab 

Dear, I have one more question about this case. If I have a list of Killing vectors, how can I do an inner product between a Killing vector with any quantity, for example, with a scalar?

@ecterrab

Thank you for attention! It was my fault, I made a mistake.

@John2020 

Thank you! Your tip worked for me too!

@ecterrab 

Here's the file...

test.mw

@vv 

Take your time but I'm waiting for the method.

Thanks!

@Mac Dude 

Thanks for your contribution!

@vv 

I thought your suggestion quite interesting but could not finish the calculation.

I waited mare than 10h and nothing happened.

Even so, thank you!

@Carl Love 

For sure, it's not a linear system!

Your suggestion worked perfectly for me! Thank you very much!