Midpoint Riemann sums Complete the following steps for the given function, interval, and value of n.


ƒ(𝓍) = 2x + 1 on [0,4] ; n = 4


d) Calculate the midpoint Riemann sum.

Verified step by step guidance

1. Step 1: Understand the problem. The midpoint Riemann sum is a method to approximate the area under a curve by dividing the interval into subintervals, calculating the function value at the midpoint of each subinterval, and summing the areas of the rectangles formed. Here, the function is ƒ(𝓍) = 2x + 1, the interval is [0,4], and n = 4 (number of subintervals).
2. Step 2: Divide the interval [0,4] into n = 4 equal subintervals. The width of each subinterval, Δx, is calculated as Δx = (b - a) / n, where a = 0 and b = 4. Substitute the values to find Δx.
3. Step 3: Determine the midpoints of each subinterval. The midpoints are calculated as the average of the endpoints of each subinterval. For example, the first subinterval is [0,1], so its midpoint is (0 + 1) / 2 = 0.5. Repeat this for all subintervals.
4. Step 4: Evaluate the function ƒ(𝓍) = 2x + 1 at each midpoint. Substitute each midpoint value into the function to find the function values at those points.
5. Step 5: Multiply each function value by the width of the subinterval, Δx, and sum these products to calculate the midpoint Riemann sum. This sum represents the approximate area under the curve on the interval [0,4].

Key Concepts

Riemann Sums

Riemann sums are a method for approximating the definite integral of a function over a specified interval. They involve dividing the interval into smaller subintervals, calculating the function's value at specific points within these subintervals, and then summing the products of these values and the widths of the subintervals. The midpoint Riemann sum specifically uses the midpoint of each subinterval to evaluate the function.

Midpoint Rule

The midpoint rule is a specific type of Riemann sum that uses the midpoint of each subinterval to estimate the area under a curve. For a function f(x) over an interval [a, b] divided into n equal parts, the midpoint of each subinterval is calculated, and the function is evaluated at these midpoints. The sum of these values, multiplied by the width of the subintervals, provides an approximation of the integral.

Definite Integral

A definite integral represents the signed area under a curve defined by a function f(x) between two points a and b on the x-axis. It is calculated as the limit of Riemann sums as the number of subintervals approaches infinity. The definite integral provides a precise value for the area, which can be interpreted in various contexts, such as total distance, accumulated quantity, or net change.