HP Forums

Full Version: Feature request: Template for n-th differential of function
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Yesterday I tried to take the second derivative of a function, but entering was really a pain, since there I did not find a template for entering something like this.

Today I already found out that one can use the template for the first derivative and as variable enter something like "x,x" for higher order derivatives. This made it less painful. Here is an example how to enter a second order derivative:
[Image: %5CLARGE%5C%21%5Cfrac%7B%5Cpartial%20e%5...2Cx%7D.gif]
I could not find this in the on-line help on the calc, but only in the PDF manual.

However after pressing "Enter" this is "optimized" (the german term "verschlimmbessern" fits perfectly here ^^) to look like that:
[Image: %5CLARGE%5C%21%5Cfrac%7B%5Cpartial%20%5C...20x%7D.gif]

And of course this becomes worse for higher order derivatives.

Hence it would be nice to have a template for those higher order derivatives like so:
[Image: LSoCIw]

Or maybe as a quick fix, the "optimization" for such higher order derivatives should be switched off.

P.S. Please complain if the inserted equations do not show up correctly for you. I used texify and at least for the last equation the forum software or my browser had problems to parse the link to the image correctly. Hence I used an URL shortener to insert the last equation which worked better.
If I recall correctly, one may use "x$n" (with n being a an positive integer) for higher order derivatives as opposed to just using "x" (or a comma-separated list of variables).

The "x,x" notation is likely a template-equivalent of doing: diff(f,x,x) which gives the second derivative of f with respect to x. Similarly, diff(f,x,y) would result in the second mixed partial derivative.

Edit: It appears that the "x$n" works on the command only; e.g. diff("3x^2-2x","x$2") -- I was not able to apply this to the template.

you should also be able to use the ' as in sin(x)'' for the 2nd order derivative of sin(x).

Reference URL's