These were the last two questions in a tutorial I had today but ran out of time before reaching them. Sadly answers dont get posted to the tutorials so I'm unsure on how to do these:
e) Find the Green’s function:
ODE: $$\frac{d^2}{dx^2}$$g(x, s) − g(x, s) = δ(x − s), 0 < x < 1,
BC: g(0, s) = g(1, s) = 0.
f) Use the Green's function to solve:
ODE: u''− u = 1, 0 < x < 1,
BC: u(0) = u(1) = 0.