Using Castigliano's theorem, find the deflection in the vertical direction for pin A of the truss in Fig. 3.25. Each member has a cross-sectional area "A" and is nonlinear-elastic with a stress-strain law given as:
![674_94983497-6094-418a-978b-20ad05309be1.png](https://secure.tutorsglobe.com/CMSImages/674_94983497-6094-418a-978b-20ad05309be1.png)
Also solve the problem by method of virtual work.
![1196_b5c54e03-fbe5-4d2e-87c6-96ba96ab810e.png](https://secure.tutorsglobe.com/CMSImages/1196_b5c54e03-fbe5-4d2e-87c6-96ba96ab810e.png)