Using solve command, to solve user defined function

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Roohullah Ansari on 17 Feb 2022
Answered: Prateek Rai on 21 Feb 2022
Suppose I write a function f(a,b,c,d).
I want to solve it using solve as
solve(b=1/f(a,b,c,d))
but whenever i used the above it gives error, showing use symb variable.
Torsten on 17 Feb 2022
You defined a,b,c and d as symbolic ? You want to solve b=1/f(a,b,c,d) for b ?
Then
bsol = solve(b*f(a,b,c,d)==1,b)
should work.

Prateek Rai on 21 Feb 2022
Hi,
You can use "syms" to create symbolic function with four arguments:
syms f(a,b,c,d)
here, f is abstract symbolic function. It does not have symbolic expressions assigned to it.
Then, specify the following formula for f.
% formula for f
After that, you can use "solve" function:
solve(b==1/f(a,b,c,d))
Please refer to syms MathWorks documentation page to find more on creating symbolic functions. You can also refer to solve MathWorks documentation page to learn more about Equations and systems solver.