Diffrerentiate y=cos^{4} (3x+1)

Ahouse has the following electrical appliance usage (1) single 40w lamp used for 4 hours per day (2) single 60w fan used for 12 hours per day (3) single 200w refrigerator that runs 24 hours per day with compressor run 12 hours and off 12 hours find the solar power inverter size in watt with correction factor of 1.25.

What precautions should you take to prevent injuries when dealing with heavy loads?

How to increase the thermal officiency of an ideal simple rankino cycle? among these methods, which one is the best and why?