In the context of the one-dimensional heat equation, there's a rod of length L with the boundary conditions being that the temperature of the whole rod is equal to T0 at time t=0 and that the neighboring temperature was held at T=0 at all times. The solution is:
u(x,t) = Σ(n=1)^(∞) (4T0)/((2n+1)π)sin(((2n+1)πx)/(L))e^(-α((2n+1)^(2)π^(2)t)/(L^(2)))
We can assume that the rod is perfectly insulated with negligible thickness, i.e., heat only moves horizontally, and there are no external heat sources or sinks. Without the boundary conditions changing, the rod is no longer at a sustained temperature, so the initial temperature changes collinearly, and it's now initially zero on the left-hand side and T0 on the right-hand side.
a) Derive the equation that represents the variation of temperature throughout the rod over time, considering our new initial temperature distribution.
b) Perform the same procedure as in part a), but now consider a different initial condition for the temperature distribution in the rod, which is given as:
u(x,0) = T0 sin((πx)/(L))