3. Consider the definite integral sin(x' ) dx. (a) The function f(x) = sin(x2) is increasing on the interval [0, 1]. Find the smallest value of n such that the difference between the upper Un and lower In Riemann sums is within 0.2. (b) Use the value of n found in part (a) to compute the lower and upper Riemann sums with n intervals and give an estimate of the value of [ sin(x?) dx