right riemann sum?

Question

the following sum (1/(1+3/n))*3/n + (1/(1+6/n))*3/n + (1/(1+9/n))*3/n + ... + (1/(1+3n/n))*3/n

is a right Riemann sum for a certain definite integral. using a partition of the interval [1,4] into n subintervals of equal length, the integrand must be the function f(x) =

Answer 1

f(x) = 1/x, I'd say, since the 3/n common to each term is the interval width, and the 1/(1+3/n) is the function argument in 3/n increments from 1 to 4. that (1+3/n) on the bottom of the fraction is the sequence of x values.

Answer 2

The function would have to be
f(x) = 1/(1+x)