How can I express a symbolic variable in function of other symbolic variables,

hello

is there a predefined function in matlab that can express a symbolic variable depending on other symbolic variables, for example

syms x y z

z=x^2+y^3;

x=f(y,z)=?????????????????

what is a function that allows to write x in terms of y and z

thanks in advance

[Sean de Wolski]

Like a function in a separate file that takes in x and y or like your expression for z which could be rewritten as

z = @(x,y)x^2+y^2;

Then to use:

z(x,y)

Answer 1

[Walter Roberson]

With newer MATLAB versions, you can use

syms f(y,z)
f(y,z) = x^2+y^3;

[XAXRXTX]

this is incorrect.

the question was how to calculate x in funtion of y and z ???

[Walter Roberson]

syms x y z
X = solve(z = x^2+y^3, x);

Note: there will be multiple solutions.

[XAXRXTX]

thanks walter, it works but you must add a quotes

syms x y z

X = solve('z = x^2+y^3', x);

[Walter Roberson]

Whether quotes are needed or not depends on the MATLAB version.

Answer 2

[Andrei Bobrov]

syms x y z
xfun = matlabFunction(solve(x^2+y^3 == z,x))

[XAXRXTX]

no that return the solution of the equation

x^2+y^3 = 0 in terms of y !!!!

Thanks however

[Andrei Bobrov]

corrected

[XAXRXTX]

thanks again andrei, but you must add a quotes and eliminate =

syms x y z

xfun = matlabFunction(solve('x^2+y^3 = z',x))