In the pinned truss shown in Mg. P10.11, pin 3 is fixed. The pin at 1 is free to move in a vertical guide, and the pin at 2 can only move along the horizontal guide. If a force P is applied at pin 2 as shown, determine u2 and vl in terms of P. Calculate all reaction forces at pins 1, 2, and 3, and check to see whether equilibrium is satisfied. Formulate the stiff-ness matrix with factor E All by the finite element method.