Assembling Jacobian Iterative method when the source term is not a matrix

I want to compute the approximations Ti for i=1,..n by solving the linear system AT=b, A is sparse matrix and

b=(f(x1); f(x2); .. f(xn)).

I need help how to assemble in Jacobi iterative method to calculate T. Let

f(x) = 15π²sin(πx)