How to solve this equation in Matlab

capacitance2=@(e,vch)1.602*10^-10*((2*q^2)/(4*k*T*pi*((hbar*v)^2)))*((sqrt(2/pi)*s.*exp(-(e.^2)/(2*s^2))+(e.*(erf((e)/(sqrt(2)*s))))).*(sech((e-(vch*q))/(2*k*T)).^2));

eqn=vch+((integral2(capacitance2,-inf,inf,0,vch))/(cpad))+vdirac==vgate; %Here vdirac, cpad and vgate are known and constant

m=solve(eqn,vch)

%There is an error coming as defined a variable to solve equation.

[Andrei Bobrov]

What is it - 'e'?

[Aniruddh Singh Shekhawat]

Vch

Answer 1

[Adam Setters]

You need to use the symbolic toolbox and declare vch and any other unknowns as symbolic variables.

These two links should help: http://www.mathworks.com/help/symbolic/create-symbolic-numbers-variables-and-expressions.html

http://www.mathworks.com/help/symbolic/solve.html