Using R to generate independent random variable X and Y, respectively, from N(0,1) and a F-distribution with degrees of freedoms 4 and 9.

Using R to generate independent random variable X and Y, respectively, from N(0,1) and a F-distribution with degrees of freedoms 4 and 9. Use nobs=4000 simulated observations of each variable to approximate the mean E(X^2 /Y).  Please attach R commands.