In: Math
a) Prove, using the joint density function, and the definition of expectation of a function of two continuous random
variables (i.e., integration) that E (5X + 7Y ) = 5E (X ) + 7E (Y ).
b)
(h) Prove, using the joint density function and the definition of expectation of a function of two continuous random
variables (i.e., integration) that Var (5X + 7Y ) = 25Var (X ) + 49Var (Y ) + 70Cov (X; Y ).