Write down a tridiagonal linear system of dimension 3 or dimension 5 to solve the problem:

−2u''(x) + u(x) = 61 [1 − (x − 0.5)²] for x ∈ (0, 1)

u(0) = 2 and u(1) = 3

With step-size n = 4 (i.e., with x₀ = 0 and x₄ = 1).