# HP Forums

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In my casio scientific calculator, when I'm in complex mode, I can make an expression using the variable x, and then I press the "Calc" button and it will replace x by an input, which can be complex.

In the HP Prime, is there any way where I can quickly calculate the value of a single-variable expression for a complex valued input?

The numeric app, both the function and the advanced functions, set to "BuildYourOwn", does not accept complex-valued inputs.

Despite the alleged purpose of the Home mode, which is to do numeric calculations, there is no way to quickly and conveniently evaluate a single-variable expression at a complex-valued input.

Casio Example, complex mode, 2 button presses to evaluate expression:
1. type x^2+1
2. press "Calc"
3. type 2i
4. press "="
Open Function App
type your single variable in. say F1
@HOME or CAS
type F1(2i);
F1({1,2,3,3+3i, 4i}) to build a table
You can use 'subst' in CAS mode: subst(x^2+1,x=2i)

CAS mode is appropriate here because you're doing an algebraic operation.
The quickest way to evaluate an expression at a value is to use the vertical bar "where" function, i.e. where x = some value.

x^2+1|x = 2*i

The vertical bar is found on the top row of the templates. On the virtual calculator, just use the vertical bar (pipe) key.

Is this what you had in mind?
(11-13-2018 03:59 AM)Wes Loewer Wrote: [ -> ]The quickest way to evaluate an expression at a value is to use the vertical bar "where" function, i.e. where x = some value.

x^2+1|x = 2*i

The vertical bar is found on the top row of the templates. On the virtual calculator, just use the vertical bar (pipe) key.

Good idea! That's what I'd use on the TI CAS calculators (where it is called the "with" operator), but I forgot it existed on the Prime.
(11-12-2018 10:02 PM)toshk Wrote: [ -> ]Open Function App
type your single variable in. say F1
@HOME or CAS
type F1(2i);
F1({1,2,3,3+3i, 4i}) to build a table

That is what I was looking for. Slightly clunkier than what I was used to in the CASIO.
The numeric mode should support displaying tables of complex valued outluts, and so should plotting, as well.
Is there a way to set the unused touch menus @home or @cas to custom functions in the HP Prime? Most of the touch row is completely unused when typing, I can think of a lot of useful things that could be put there.
Reference URL's
• HP Forums: https://www.hpmuseum.org/forum/index.php
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