@DavidZ I have a few classes that I clean when I encounter them. (1) Thank your and similar that have nothing but a courtesy and are more than about 1 hour old. (2) Any comment which serves no purpose but to say how the commenter voted. (3) Comments asking about (down)votes and more than about 1 hour old. (4) Comments asking for votes or accepts.

@JKS Frankly that is something you should be able to work out for yourself.

hi

Hi.

@dmckee seems reasonable

I thought we had a physics-people tag. Seems we don't.

Anybody good at math want to explain something? I have two vectors and I need to take the derivative of one with respect to the other (which gives a matrix), but it's terms like \frac{\partial u}{\partial \rho u}

And it's a little confusing how you take derivatives with respect to a product and not just a variable

Bonus points if it can be done in Mathematica so I don't have to do it by hand a whole bunch of times

By taking a derivative with respect to a vector, are you talking about a gradient?

Anyway, taking a derivative with respect to a product, or any expression, is perhaps best thought of as making a new variable to represent the expression, doing the substitution, taking the derivative with respect to the substituted variable, and then substituting back

I don't know that Mathematica has any shortcut for that. I've looked.

I have a HW like question that I'd like to pose to anybody in chat, it should be a fairly quick one

@Astrum You can post. If it's interesting somebody might take a look.

@BrandonEnright unfortunately I think it might be a little too much like HW

@Astrum Nothing, barring offensive, abusive, or hateful stuff, is off topic in chat.

it should actually be a quick explanation as well, so I think a post is too much for it

I just came across a really weird thing in Morin CM, and I really can't figure out how he sets the problem up. Everything after is quick

If I posted for every little question I had, I'd have about a thousand silly posts by now

does this chat support latex like the Math chat? $F=ma$

o cool!

:

hmm...

google "5+​(‑sqrt(​1-​x^​2-​(y-​abs(​x))^​2))*​cos(​30*​(1-​x^​2-​(y-​abs(​x))^​2))"