so...here it is that equation:

du/dt   = d²u/dr² +  du/r*dr  +  u  +  f(r,t);     r=(0,...,2]; t(0,...,1]

also we have conditions:

u(r,0)=0;

u(0,t)=t^2;

u(2,t)=0

I need to find u(r,t) and to graph it

r and t are cylindric coordinates.

f(r,t) is some definite function.