creating equidistant mesh of (0, 1) with 20 elements...
stiffness matrix = 
TridiagonalMatrix(diag=[20, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 20], lower=[-20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20], upper=[-20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20, -20])
load vector = 
[0.025, 0.055, 0.06, 0.065, 0.07, 0.075, 0.08, 0.085, 0.09, 0.095, 0.1, 0.105, 0.11, 0.115, 0.12, 0.125, 0.13, 0.135, 0.14, 0.145, 0.075]