Questions: Let f be the function graphed below. If three subintervals of equal length are used, draw rectangles whose area represents a right Riemann sum approximation of ∫ from 1 to 5.5 of f(x) dx.
Width of each subinterval: □
The shaded area above, representing a right Riemann sum, is an of the integral ∫ from 1 to 5.5 of f(x) dx because the function is on the interval 1<x<5.5.
Transcript text: Let $f$ be the function graphed below. If three subintervals of equal length are used, draw rectangles whose area represents a right Riemann sum approximation of $\int_{1}^{5.5} f(x) d x$.
Width of each subinterval: $\square$
The shaded area above, representing a right Riemann sum, is an of the integral $\int_{1}^{5.5} f(x) d x$ because the function is on the interval $1
Solution
Solution Steps
Step 1: Calculate the width of each subinterval
The interval is from 1 to 5.5, so the total length is 5.5 - 1 = 4.5. We're using 3 subintervals, so the width of each is 4.5 / 3 = 1.5.
Step 2: Determine the right endpoints of the subintervals
The subintervals are:
[1, 2.5], [2.5, 4], [4, 5.5]
The right endpoints are 2.5, 4, and 5.5.
Step 3: Draw the rectangles
Draw rectangles with the right endpoints determining the height and the calculated width (1.5). The first rectangle goes from x = 1 to x = 2.5, with height f(2.5). The second rectangle spans from x = 2.5 to x = 4, with a height of f(4). The last rectangle extends from x = 4 to x = 5.5, and its height is given by f(5.5).
Step 4: Determine if the Riemann sum is an over or under approximation
Since the function is increasing on the interval (1, 5.5), the right Riemann sum will be an overestimate.
Final Answer
Width of each subinterval: 1.5
The shaded area above, representing a right Riemann sum, is an overestimate of the integral $\int_{1}^{5.5} f(x) dx$ because the function is increasing on the interval $1 < x < 5.5$.