What do I do next to solve for m?

clear
syms f m g L I
E = 2*pi*f == sqrt((m*g*L)/I) 

E = 

%What is the mass when...
m = solve(E,m)

Warning: Solutions are only valid under certain conditions. To include parameters and conditions in the solution, specify the 'ReturnConditions' value as 'true'.

m = 

subs(E, f ,0.1);
subs(E, I, 50);
subs(E, g, 9.8);
subs(E, L, 0.5);

Now I need to find a value for m but I'm not sure how to move forward with it

Answer 1

[Star Strider]

The conditions only apply if the values of the constants are not defined first.

Try this —

syms f m g L I 
f = sym(0.1);
I = sym(50);
g= sym(9.81);
L = sym(0.5);
E = 2*pi*f == sqrt((m*g*L)/I);
m = solve(E,m)

m = 

m_vpa = vpa(m, 42)

m_vpa = 

4.02430352745743470696615331289547446903719

.

[Amy Joyce Valencia]

Do I have to use syms for every valuable? Or is there a way to shorten it?

[Star Strider]

It’s not necessary to use the Symbolic Math Toolbox at all —

f = 0.1;
I = 50;
g = 9.81;
L = 0.5;
E = @(m) 2*pi*f - sqrt((m*g*L)/I)                           % Anonymous Function

E = function_handle with value:
    @(m)2*pi*f-sqrt((m*g*L)/I)

m = fzero(E, 10)

m = 4.0243

Although it only shows four decimal places, it retains full internal precison, so nothing is lost.

.