Consider the following limit of Riemann sums of a function f on [a,b]. Identify f and express the limit as a definite integral. lim Δ→0
​
∑ k=1
n
​
x k
∗
​
tan 2
x k
∗
​
Δx k
​
;[1,2] The limit, expressed as a definite integral, is (Simplify your answers.)