Strange "solve" error and undefined "vpasolve"

Hi,

When trying to use the "solve" function for one of the doc examples it only returns the sym variable. It doesn't even solve the equation x+1==0, when using the syntax:

        syms x
        solvex=solve(x+1==0,x)

it only returns solvex=x. Even worse, it does not even recognize vpasolve as a function and gives the error: "Undefined function or variable 'vpasolve'". Any help would be greatly appreciated.

/Philip

[Walter Roberson]

Is it possible that at some point you installed the Maplesoft MATLAB Connector, which is an interface that permits MATLAB to call into Maple ?

[Philip Croné]

Yes, I would say that's highly possible!

Answer 1

[Star Strider]

This may be a path problem.

Try typing these either in your Command Window or a script:

restoredefaultpath 
rehash toolboxcache

If that does not solve your problem, request Tech Support through the Contact Us link at the top right corner of this page.

[Philip Croné]

Worked like a charm. Thank you!

[Star Strider]

As always, my pleasure!

[Francisco Lopes]

I solved this kind of problem using:

syms z

before the solver command.

Ex.:

syms z

Sol = solve(fA == 0, fB == 0);

Justifying: Matlab needs treat z symbolic in order to handle the different solutions.

[Star Strider]

@Francisco Lopes — That wasn’t actually the original problem.

Answer 2

[MohammadMahdi MovahedFar]

You should write:

S = vpasolve(...)

Without assignment it won't work.

[Star Strider]

@MohammadMahdi MovahedFar — Not true.

Proof —

        syms x
        vpasolve(x+1==0,x)

ans = 

.

[Walter Roberson]

The original problem was that the user had installed the Maplesoft Maple symbolic interface, which does not define a function named vpasolve . Requiring output for an undefined function does not fix the problem that the function is undefined.