1.[4] The following limit is equal to the area under the graph of some function f over some interval [a, b]. Determine the function and the interval. (Do not evaluate the limit). n 7i lim 1 n-oo n i=1 2.[4] Express the definite integral as a limit of Riemann sums. (Do not attempt to evaluate the limit): x dx 1 + x2 3.[4] The piece-wise function f is defined as follows: f(x) = $3, if0