For the functions, evaluate the given expressions.

f(x,y) =square root of: 99x²y²

, findf(3,9)

g(x,y) = lnx⁶+y², findg(0,e)

For two cities with populationsxandythat aredmiles apart, the number of telephone calls per hour between them can be estimated by the function of three variables

f(x,y,d) =3xy/d²

.

(This is called thegravity model.)Use the gravity model to estimate the number of calls between two cities of populations40,000and60,000that are500miles apart.