Riemann Sums: Approximating Areas

The area bounded by the function f(x)f\left(x\right) and the xx-axis in the interval [a,b]\left[a,b\right] is given by limni=1n4in2[ein]\displaystyle \lim_{n\to\infty}\sum_{i=1}^n\frac{4i}{n^2}\left[e^{\frac{i}{n}}\right].

Determine f(x)f(x), aa, and bb.
More Riemann Sums Questions:
More Approximating Areas & Riemann Sums Questions: