Function File: lfdif (a, b, alpha, beta, n)

Approximate the solution of a boundary-value problem. The problem is defined as

           y''=p(x)*y' + q(x)*y + r(x), a<=x<=b, y(a)=alpha, y(b)=beta

by the linear finite-diffence method. The inputs are

a, b

Endpoints

alpha, beta

boundary conditions

n

An integer value greater than or equal to 2