Please solve these 3 problems with some explanations so that I can compare them with my approach.

1) For the random variable X with pdf f(x) = 1 /x if x 21 0 otherwise a) Find the cdf of X b) Find the median of X. c) Find the 75th percentile of X. 80 2) If X and Y have joint density fry (x, y) = -(x2 + y) for 0S x $2 and 0 S y S 4, and equal to O elsewhere, find fy (x) and fy(y) , the marginal probability densities of X and Y 3) Let X and Y be random variables with joint pdf fry (x, y) = 2e"(*) for 0