MATLAB: Symbolic equation with numeric variable

MATLABsymbolic

Is it possible to use a numeric variable(in this case "alfa") in a symbolic equation.
I'm trying to solve the symbolic q. I need the flexibility to change the value of alfa. However if i use the term "alfa" when defining the eqn, marlab fails to solve the equation.
If I manually type the value of alfa inside the equation, the programs runs without a problem.
f=50;
w=2*pi*f;
R=303.47/50;
alfa=72;
syms q;
eqn = 'sin(72*pi/180) == cos(q) * exp(tan(q) * (pi/6 - 72*pi/180 + q))';
% This is the format I want to use,but gives errors
%----------------------------------------------------------------------

%eqn = 'sin(alfa*pi/180) == cos(q) * exp(tan(q) * (pi/6 - alfa*pi/180 + q))';  
%----------------------------------------------------------------------
y= double(solve(eqn));
C=1/(w*R*tan(y)) /10^(-6)  % Capacitor Value

Best Answer

eqn = subs('sin(alfa*pi/180) = cos(q) * exp(tan(q) * (pi/6 - alfa*pi/180 + q))', 'alfa', alfa);
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