Deepak Kumar you can find the solution in the following figure!!!In your case the RL (in the figure below) is infinity and the RS (in the figure below) is 2Rss.You can replace this terms and the results will be the same. This link may help you also for other problems (Solution in page 12). http://aries.ucsd.edu/NAJMABADI/CLASS/ECE65/12-W/NOTES/Amp-2.pdf
