What is the Heat equation form $u_t = u_{xx} + f(x)$.What is this $f(x)$ means.
In the question here it is used.
(That is it hasn't asked to change $u_t = \alpha^2 u_{xx}$ as $ u_t = u_{xx} + f(x)$) but as in that link f(x) range of values are given.In that case can I add f(x) to the heat equation $u_t = \alpha^2 u_{xx}$ and solve the problem in a similar way.
What is the role of f(x) here and in the derivation of heat equation how does it appear?