Riemann Sum Definition & Limits

The limit definition of the definite integral and expressing limits as Riemann sums.

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Riemann Sum Definition & Limits

38 questions

AP Learning Target(s): LT 3: Riemann Sums, Summation Notation, and Definite Integral Notation

Definite Integral as Limit of a Riemann Sum

The expression lim(n→∞) Σ(i=1 to n) f(xi*)Δx defines a definite integral. If f(x) = x² on the interval [1, 4] and Δx = (4-1)/n, which of the following is equivalent to this limit?

  1. A.

    $\displaystyle\int_{1}^{4}$ x² dx

  2. B.

    $\displaystyle\int_{1}^{4}$ 2x dx

  3. C.

    $\displaystyle\int_{0}^{4}$ x² dx

  4. D.

    lim(n→∞) Σ(i=1 to n) (1 + 3i/n)² · (3/n)

Correct answer: A
Definite Integral as Limit of Riemann Sum

If lim(n→∞) Σᵏ⁼ⁿₖ₌₁ f(2 + 3k/n)·(3/n) = 12, which of the following definite integrals has a value of 12?

  1. A.

    $\displaystyle\int_{25}$ 3f(x) dx

  2. B.

    $\displaystyle\int_{03}$ f(2 + x) dx

  3. C.

    $\displaystyle\int_{25}$ f(x) dx

  4. D.

    $\displaystyle\int_{25}$ f(2 + 3x) dx

Correct answer: C
Definite Integral as Limit of Riemann Sum

Let the interval $[a,b]$ be partitioned into $n$ subintervals of equal width, and for a function $h$, let $c_i$ be any point in the $i$-th subinterval. If $$\lim_{n\to\infty} \sum_{i=1}^{n} h(c_i) \frac{b-a}{n} = 7$$, which of the following statements must be true?

  1. A.

    h(b) - h(a) = 7

  2. B.

    h(x) = 7/(b-a) for all x in [a,b]

  3. C.

    $$\int$$ₐᵇ h(x) dx = 7

  4. D.

    The average value of h on [a,b] is 7

Correct answer: C
Integral as a Limit of a Riemann Sum

Which of the following expressions represents the definite integral $\displaystyle\int_{0}^{\pi}$ sin(x) dx as a limit of a Riemann sum?

  1. A.

    lim[n→∞] Σ[i=1 to n] sin(π/i)·(π/n)

  2. B.

    lim[n→∞] Σ[i=1 to n] sin(πi/n)·(π/n)

  3. C.

    lim[n→∞] Σ[i=1 to n] sin(i)·(π/n)

  4. D.

    lim[n→∞] Σ[i=0 to n-1] sin(πi/n)·(π/n)

Correct answer: B
Limit of a Riemann Sum

Which of the following definite integrals is equal to $$\displaystyle\lim_{n \to \infty} \frac{1}{n} \sum_{k=1}^{n} \left(\frac{k}{n}\right)^2$$?

  1. A.

    $$\displaystyle\int_{0}^{1} \sqrt{x} dx$$

  2. B.

    $$\displaystyle\int_{0}^{1} x dx$$

  3. C.

    $$\displaystyle\int_{0}^{1} x^2 dx$$

  4. D.

    $$\displaystyle\int_{1}^{2} x^2 dx$$

Correct answer: C
Limit of a Riemann Sum

The expression $$\lim_{n \to \infty} \sum_{i=1}^n f(a + i \Delta x) \Delta x$$, where $$f$$ is a continuous function and $$\Delta x = \frac{b-a}{n}$$, is equivalent to:

  1. A.

    $$\int_{a+\Delta x}^{b} f(x) dx$$

  2. B.

    $$\int_{a}^{b} f(x) dx$$

  3. C.

    $$\int_{a}^{b} f'(x) dx$$

  4. D.

    $$\int_{a}^{a+\Delta x} f(x) dx$$

Correct answer: B
Number of Rectangles in a Riemann Sum

To approximate the value of a definite integral using a right Riemann sum with 5 equal subintervals, how many rectangles are required?

  1. A.

    6

  2. B.

    4

  3. C.

    10

  4. D.

    5

Correct answer: D
Primary Purpose Of A Riemann Sum

What is the primary purpose of using a Riemann sum?

  1. A.

    Determine function continuity

  2. B.

    Find limits of sequences

  3. C.

    Solve differential equations

  4. D.

    Approximate definite integrals

Correct answer: D
Purpose of Riemann Sums

A Riemann sum is primarily used for which of the following?

  1. A.

    Determine function continuity

  2. B.

    Approximate definite integrals

  3. C.

    Find limits of sequences

  4. D.

    Solve differential equations

Correct answer: B
Riemann Sum and Definite Integral Relationship

Which statement best describes the relationship between a Riemann sum and a definite integral?

  1. A.

    A Riemann sum is equivalent to a definite integral.

  2. B.

    A Riemann sum is the antiderivative of a function.

  3. C.

    A Riemann sum is an approximation of the definite integral.

  4. D.

    A Riemann sum represents the derivative of a function.

Correct answer: C
Riemann Sum and Integrability

If the equation `lim[n→∞] Σ[i=1 to n] f(c_i)Δx = $\displaystyle\int_{2}^{5}$ f(x) dx` holds, where `c_i` is a point in the `i`-th subinterval `[x_{i-1}, x_i]` of a partition of `[2, 5]`, which of the following properties must the function `f` possess?

  1. A.

    f(x) must be integrable on [2,5]

  2. B.

    f(x) must be continuous on [2,5]

  3. C.

    f(x) must be increasing on [2,5]

  4. D.

    f(x) must be differentiable on [2,5]

Correct answer: A
Riemann Sum as a Definite Integral

Which definite integral is given by the limit $$\displaystyle\lim_{n \to \infty} \frac{2}{n} \sum_{k=1}^{n} \ln\left(1 + \frac{2k}{n}\right)$$?

  1. A.

    $$\displaystyle\int_{0}^{1} \ln(1 + x) dx$$

  2. B.

    $$\displaystyle\int_{0}^{2} \frac{1}{1 + x} dx$$

  3. C.

    $$\displaystyle\int_{1}^{3} \ln(x) dx$$

  4. D.

    $$\displaystyle\int_{0}^{1} \ln(1 + 2x) dx$$

Correct answer: C
Riemann Sum as a Definite Integral

Find the value of $$b$$ for which $$\displaystyle \int_{1}^{b} x^2 dx = \lim_{n \to \infty} \sum_{k=1}^{n} \left(1 + \frac{2k}{n}\right)^2 \frac{2}{n}$$

  1. A.

    $$b = 2$$ only

  2. B.

    $$b = 3$$ only

  3. C.

    There is no such value of $$b$$.

  4. D.

    $$b$$ could be any real number.

Correct answer: B
Riemann Sum as a Definite Integral

Which of the following definite integrals is equal to $$\displaystyle\lim_{n \to \infty} \frac{\pi}{2n} \sum_{k=1}^{n} \sin\left(\frac{\pi k}{2n}\right)$$?

  1. A.

    $$\displaystyle\int_{0}^{1} \sin\left(\frac{\pi x}{2}\right) dx$$

  2. B.

    $$\displaystyle\int_{0}^{\pi/2} \sin(x) dx$$

  3. C.

    $$\displaystyle\int_{0}^{\pi/2} \cos(x) dx$$

  4. D.

    $$\displaystyle\int_{0}^{\pi} \sin(x) dx$$

Correct answer: B
Riemann Sum as a Definite Integral

Which of the following definite integrals is equal to $$\displaystyle\lim_{n \to \infty} \frac{1}{n} \sum_{k=1}^{n} \sqrt[3]{1 + \frac{k}{n}}$$?

  1. A.

    $$\displaystyle\int_{0}^{1} \sqrt{1 + x} dx$$

  2. B.

    $$\displaystyle\int_{1}^{2} \sqrt[3]{x} dx$$

  3. C.

    $$\displaystyle\int_{0}^{1} (1 + x)^2 dx$$

  4. D.

    $$\displaystyle\int_{0}^{1} \sqrt[3]{2 + x} dx$$

Correct answer: B
Riemann Sum as a Definite Integral

Which of the following definite integrals is equal to $$\displaystyle\lim_{n \to \infty} \frac{4}{n} \sum_{k=1}^{n} \sqrt{3 + \frac{4k}{n}}$$?

  1. A.

    $$\displaystyle\int_{0}^{4} \sqrt{x} dx$$

  2. B.

    $$\displaystyle\int_{0}^{3} \sqrt{3 + x} dx$$

  3. C.

    $$\displaystyle\int_{0}^{1} \sqrt{3 + 4x} dx$$

  4. D.

    $$\displaystyle\int_{3}^{7} \sqrt{x} dx$$

Correct answer: D
Riemann Sum as a Definite Integral

Which of the following definite integrals is equal to $$\displaystyle\lim_{n \to \infty} \frac{1}{n} \sum_{k=1}^{n} e^{\frac{k}{n}}$$?

  1. A.

    $$\displaystyle\int_{1}^{2} e^x dx$$

  2. B.

    $$\displaystyle\int_{0}^{1} e^x dx$$

  3. C.

    $$\displaystyle\int_{0}^{1} xe^x dx$$

  4. D.

    $$\displaystyle\int_{0}^{1} e^{2x} dx$$

Correct answer: B
Riemann Sum as a Definite Integral

Which of the following is equal to $$\displaystyle\lim_{n \to \infty} \frac{1}{n} \sum_{k=1}^{n} \frac{k}{n} \cdot e^{\frac{k}{n}}$$?

  1. A.

    $$\displaystyle\int_{0}^{1} x^2 e^x dx$$

  2. B.

    $$\displaystyle\int_{1}^{2} x e^x dx$$

  3. C.

    $$\displaystyle\int_{0}^{1} e^x dx$$

  4. D.

    $$\displaystyle\int_{0}^{1} x e^x dx$$

Correct answer: D
Riemann Sum as a Definite Integral

Which of the following definite integrals is equal to lim(n→∞) Σᵏ⁼ⁿₖ₌₁ sin(πk/n)·(π/n)?

  1. A.

    $\displaystyle\int_{0}$ᵖ sin(πx) dx

  2. B.

    $\displaystyle\int_{0}^{1}$ sin(x) dx

  3. C.

    $\displaystyle\int_{0}^{1}$ sin(πx) dx

  4. D.

    $\displaystyle\int_{0}$ᵖ sin(x) dx

Correct answer: D
Riemann Sum as Definite Integral

Which of the following definite integrals is equal to the expression $$\lim_{n \to \infty} \frac{1}{n} \left( \frac{1}{2 + \frac{1}{n}} + \frac{1}{2 + \frac{2}{n}} + \cdots + \frac{1}{2 + \frac{n}{n}} \right)$$?

  1. A.

    $$\int_{1}^{2} \frac{1}{x} dx$$

  2. B.

    $$\int_{0}^{2} \frac{1}{2 + x} dx$$

  3. C.

    $$\int_{0}^{1} \frac{1}{2 + x} dx$$

  4. D.

    $$\int_{2}^{3} \frac{1}{2 + x} dx$$

Correct answer: C
Riemann Sum Definition of an Integral

Which of the following limits defines the definite integral $\displaystyle\int_{1}^{3}$ h(x)dx?

  1. A.

    lim(n→∞) Σ(i=1 to n) h(1 + 2(i-1/2)/n)·2/n

  2. B.

    lim(n→∞) Σ(i=1 to n) h(1 + 2i/n)·2/n

  3. C.

    lim(n→∞) Σ(i=0 to n) h(1 + 2i/n)·2/n

  4. D.

    lim(n→∞) Σ(i=1 to n) h(1 + 2(i-1)/n)·2/n

Correct answer: A
Riemann Sum Definition of an Integral

Which of the following limits of Riemann sums is equivalent to the definite integral $\displaystyle\int_{1}^{4}$ √x dx?

  1. A.

    lim(n→∞) Σᵏ⁼ⁿₖ₌₁ √(1+3(k-1)/n)·(3/n)

  2. B.

    lim(n→∞) Σᵏ⁼ⁿₖ₌₁ √(1+3(k-1/2)/n)·(3/n)

  3. C.

    lim(n→∞) Σᵏ⁼ⁿₖ₌₀ √(1+3k/n)·(3/n)

  4. D.

    lim(n→∞) Σᵏ⁼ⁿₖ₌₁ √(1+3k/n)·(3/n)

Correct answer: B
Riemann Sum Definition of an Integral

Which of the following expressions represents the definite integral $\displaystyle\int_{1}^{3}$ x³dx as a limit of a Riemann sum?

  1. A.

    lim(n→∞) Σᵢ₌₁ⁿ [(1 + 2i/n)³](2/n)

  2. B.

    lim(n→∞) Σᵢ₌₁ⁿ [(i/n)³](3/n)

  3. C.

    lim(n→∞) Σᵢ₌₀ⁿ [(1 + 2i/n)³](2/n)

  4. D.

    lim(n→∞) Σᵢ₌₁ⁿ [(3i/n)³](3/n)

Correct answer: A
Riemann Sum Definition of an Integral

The process of approximating a definite integral by partitioning the interval of integration into subintervals and summing the areas of rectangles is fundamental to which of the following concepts?

  1. A.

    Riemann sum property

  2. B.

    Fundamental Theorem of Calculus

  3. C.

    Constant property

  4. D.

    Symmetry property

Correct answer: A
Riemann Sum Endpoint Definitions

What is the primary difference between a right Riemann sum and a left Riemann sum?

  1. A.

    Uses midpoints instead of endpoints

  2. B.

    Uses trapezoids instead of rectangles

  3. C.

    Uses nonuniform partitions instead of uniform

  4. D.

    Uses right endpoints instead of left

Correct answer: D
Riemann Sum Evaluation Points

Which of the following statements accurately describes a key difference between a Midpoint Riemann Sum and a Left Riemann Sum?

  1. A.

    Midpoint uses endpoints

  2. B.

    Left uses midpoints

  3. C.

    Left uses right endpoints

  4. D.

    Midpoint uses midpoints

Correct answer: D
Riemann Sum Integral Definition

Which of the following definite integrals is equal to $$\displaystyle\lim_{n \to \infty} \frac{3}{n} \sum_{k=1}^{n} \cos^2\left(\frac{3k}{n}\right)$$?

  1. A.

    $$\displaystyle\int_{0}^{3} \cos^2(x) dx$$

  2. B.

    $$\displaystyle\int_{0}^{3} \sin^2(x) dx$$

  3. C.

    $$\displaystyle\int_{0}^{1} \cos^2(3x) dx$$

  4. D.

    $$\displaystyle\int_{0}^{3} \cos(x) dx$$

Correct answer: A
Riemann Sum Limit as Definite Integral

Which expression represents the limit of a Riemann sum for the function f(x) = x² on the interval [1, 4] as the number of subintervals approaches infinity?

  1. A.

    $\displaystyle\int_{1}^{4}$ x² dx

  2. B.

    lim(n→∞) Σ(i=1 to n) (3/n)·f(1 + 3i/n)

  3. C.

    lim(n→∞) Σ(i=0 to n-1) (3/n)·f(1 + 3i/n)

  4. D.

    lim(n→∞) Σ(i=1 to n) (3/n)·f(1 + 3(i-1)/n)

Correct answer: A
Riemann Sum Procedure

The table above shows selected values for a function `f`. Which of the following correctly orders the steps required to approximate the area under the graph of `f` using a Riemann sum?

x0247
f(x)161015
  1. A.

    Identify subintervals from x-values, Compute area by multiplying function value by subinterval width, Sum the areas to approximate the total area, Choose sample points based on the method

  2. B.

    Sum the areas to approximate the total area, Identify subintervals from x-values, Choose sample points based on the method, Compute area by multiplying function value by subinterval width

  3. C.

    Identify subintervals from x-values, Choose sample points based on the method, Compute area by multiplying function value by subinterval width, Sum the areas to approximate the total area

  4. D.

    Choose sample points based on the method, Compute area by multiplying function value by subinterval width, Identify subintervals from x-values, Sum the areas to approximate the total area

Correct answer: C
Riemann Sum Rectangle Width

Which of the following symbols represents the width of each rectangle in a Riemann sum?

  1. A.

    Σ

  2. B.

    ∆x

  3. C.

    $$\int$$

  4. D.

    ∇

Correct answer: B
Riemann Sum Rectangle Width

For a Riemann sum that approximates the area under a curve on the interval `[a, b]` using `n` rectangles of equal width, which expression represents the width of each rectangle?

  1. A.

    $$\frac{a+b}{2}$$

  2. B.

    $$\frac{b+a}{n}$$

  3. C.

    $$b-a$$

  4. D.

    $$\frac{b-a}{n}$$

Correct answer: D
Riemann Sum Subintervals and Accuracy

Increasing the number of subintervals used in a Riemann sum approximation generally has which of the following effects?

  1. A.

    Decreases accuracy

  2. B.

    Has no effect

  3. C.

    Increases accuracy

  4. D.

    Increases error

Correct answer: C
Riemann Sum to Definite Integral

Which of the following is equivalent to the limit of the Riemann sum lim[n→∞] Σ[i=1 to n] (3x²ᵢ)Δx over the interval [1,4], where Δx = (4-1)/n?

  1. A.

    3$\displaystyle\int_{1}^{4}$ x dx

  2. B.

    $\displaystyle\int_{1}^{4}$ 3x dx

  3. C.

    $\displaystyle\int_{1}^{4}$ 3x² dx

  4. D.

    3[4² - 1²]

Correct answer: C
Riemann Sum Variable Definition

In a Riemann sum, what does the variable n represent?

  1. A.

    It represents the change in x-value for each rectangle.

  2. B.

    It denotes the width of each rectangle.

  3. C.

    It indicates the value of the function at the right endpoint of each subinterval.

  4. D.

    It represents the number of rectangles used in the approximation.

Correct answer: D
Riemann Sums and Partitions

Which of the following approximation methods can be applied using both uniform and nonuniform partitions?

  1. A.

    All Riemann sums

  2. B.

    Only midpoint Riemann sum

  3. C.

    Only trapezoidal sum

  4. D.

    Only left Riemann sum

Correct answer: A
Riemann Sums and the Definite Integral

What is the fundamental difference between using a Riemann sum and a definite integral to determine the area under a curve?

  1. A.

    A Riemann sum provides an approximation, while an integral gives the exact value as the limit of Riemann sums

  2. B.

    A Riemann sum calculates the area above the curve, while an integral calculates the area below the curve

  3. C.

    A Riemann sum is used for continuous functions, while an integral is used for discrete data points

  4. D.

    A Riemann sum is always larger than the integral for the same curve and interval

Correct answer: A
Riemann Sums Versus Definite Integrals

What is the fundamental difference between a Riemann sum and a definite integral when used to calculate the area under a curve?

  1. A.

    A Riemann sum calculates the area above the curve, while an integral calculates the area below

  2. B.

    A Riemann sum provides an approximation, while an integral gives the exact area

  3. C.

    A Riemann sum is used for continuous functions, while an integral is used for discrete data points

  4. D.

    A Riemann sum is faster to compute, while an integral provides a more visually appealing result

Correct answer: B
Types of Riemann Sums

All of the following are types of Riemann sums EXCEPT:

  1. A.

    Right Riemann Sum

  2. B.

    Simpson's Riemann Sum

  3. C.

    Left Riemann Sum

  4. D.

    Midpoint Riemann Sum

Correct answer: B