For the bar shown in Figure P3-61 subjected to the linear varying axial load, determine the displacements and stresses using (a) one and then two finite element models and (b) the collocation, subdomain, least squares, and Galerkin's methods assuming a cubic polynomial of the form u(x) =c1x + c2x2 + c3x3. T(x) = 10x kN/m x 3.0 m- AE= 2 × 104 kN Figure P3-61