HP Prime Emulator

[Bob391]

If you run a clean copy of the HP Prime Virtual Calculator on your computer and press any letter key followed by Enter, the result isn't a value like 0, but the letter itself.

a Enter gives a

x Enter gives x

y Enter gives y

Without assigning the variable a value it defaults to itself, sorta speak.

Don't do this, it messes the Emulator up.

Suppose you do x Sto -> y

Then y Enter gives x

This is bad. Because Implicit_diff(y^5 = x,x,y) doesn't give the correct result, 1/(5*y^4).

And that seems to be unrecoverable.

How do you get (y Enter gives y) back?

You can't assign y to y; y is x.

You can do the implicit_diff() but you have to use (x,z) instead of (x,y) in the syntax.

I've tried everything I can think of. Even uninstalled the Virtual Calculator, downloaded installed a fresh copy from the web site. It still thinks y is x.

[BartdB]

Hi,

This is a feature, so for example you can define y in terms of x

e.g. let  y=x^2+2*x

then we can take dy/dx:  diff(y,x) = 2*x+2

To reset the variable use purge(), i.e. purge(y) will reset the y variable.

Now entering y ENTER will return y indicating that there is nothing stored in y.

EDIT: of course this means that it is always important to ensure you know what is stored in your variables and to clear (purge) any variables that you don't want to have substituted with its contents.

Regards