Question 9 Let a not be an integer, and f (x) = cos ar, I E (-7, 7] Extend f to PC (27). (a) Compute the Fourier series of f. (b) Discuss its pointwise convergence. (c) Apply Parseval's formula to show sin 207 1+ 207 ´sin on 2 =)' - (;. 1 ' (n² – a²)² ·

20. If 60 percent of the potential energy of water flowing over a dam can be converted to electricity, find the maximum power output, in kW (kilowatts), for a dam 50 m high where the water crosses at a rate of 300,000 kg/min (1 watt = 1 joule/sec, 1 kW = 1000 watts)

5.4 problem 34

If you double the force and double the distance, work is increased by   A. Three times (work triples)   B. Four times.   C. Two times( work doubles)   D. work increased by 2.5 times