Derivating problems

[Carsen]

Hi Wheazel:

(09-22-2018 10:32 AM)wheazel Wrote:  Thank you roadrunner,
so, as I got it now, diff works with expressions only, not with functions?

diff() should work with expressions and functions. In other words, it should work regardless if the user stores it in 'f' or 'f(x)'.

(09-21-2018 10:12 PM)wheazel Wrote:  diff(f(x),$(x,2)) or, what seems the same: diff(f(x),x$2). Both Versions return a 0, which is not correct.
diff(f(x),x) works fine, so does f', f'' and so on.

diff(f(x),x), f', and f'' are all some of the correct ways to differentiate the expression/function. May I ask why you are using diff(f(x),$(x,2)) or diff(f(x),x$2)? I've never seen this syntax for a HP Prime ever. The '$' is very confusing.

Did you use the [HELP] key on the HP Prime in the upper left part of the keyboard? To use the [HELP] key on diff(), select diff() from the Calculus menu in the CAS portion of the toolbox and put it on the Entry Line. Then simply press the [HELP] key. You can see the syntax, a description, and examples. Check it out. It should clear up syntax issues, especially with the examples.

Let me know how everything works out!