Let x and y be integers. Prove that(a) if x and y are even, then is even.(b) if x is even, then xy is even.(c) if x and y are even, then xy is divisible by 4.(d) if x and y are even, then is even.(e) if x and y are odd, then is even. (f) if x and y are odd, then is even.(g) if x and y are odd, then xy is odd. (h) if x is even and y is odd, then is odd.(i) if x is even and y is odd, then is even.

L21 - 4 ex. Ac m raim ontdatap oit000trmt hebae of a rocket launching pad. 1) If the camera to rocket distance is changing at 750 ft/sec when the rocket is 4000 ft high, how fast is the rocket rising at this time camera lauch pad