$12\mathrm{.}3-1$ A truss ABC consisting of two members $($see figure$)$ supports a vertical load $P$ at node $B.$ Each member has an axial stiffness

EA$.$ Assuming that the beta angle is $60,$ determine the following trips:

a$)$ the vertical deflection of node $B$

b$)$ the horizontal deflection of node $B$

e$)$ the angle of rotation of member $AB$

Please explain the procedure