Could you help me about calculating differentiation?

jinsuk Lee wrote: I finally came final step. Final sep is differentiaion. I tried to slove it to study by using book, PTC help and PTC site. But I can't understand well. So Please, Could you help me? I attached my files. And I also wonder how to clear in mathcad equations is long. so some equations cross line. I want to arrange

Not being able to break math regions in several lines is a big annoyance in every version of Mathcad and it got even worse in Prime (we don't even have Ctrl-+ here).

There are four ways to tidy up those expression which come to my mind.

1) Chose a smaller font size for that expression. Doesn't look good because its inconsistent unless you change the font size for all expressions in the document.

2) As you are calling alpha five times (which is quite inefficient) its agood idea anyway to just call it once and store the result in a local variable with a short name - I have chosen "t", thinking of "temporary".

3) Break the expression into several smaller parts. This is especially useful if 2) doesn't apply

4) Use a different way to calculate the desired result. in your case you could use a vector product.

Personally I would settle with 2) or 4) in case of the function I have chosen for demonstration.

As for the derivative. The way you have defined your function T its dependent on the three variables mu, theta and v only. Its NOT dependent on r, so the derivative with respect to r will be zero. If thats not what you want you have to define T() differently so that r is an argument of that function and also of the function whoch T is calling. Guess you have a design problem with your sheet.

BTW, you can only calculate the derivative with respect to a variable. In your sheet r is a function!

EDIT: I just noticed that I forget the summand with t^3 in my third (green) layout. Can't correct that mistake as I have already close Prime without saving the sheet. But I guess you get the idea anyway.