key term - Trapezoidal Rule

Definition

The trapezoidal rule is a numerical integration method used to approximate the definite integral of a function over a given interval. It is a simple and widely-used technique for estimating the area under a curve by dividing the interval into trapezoids and summing their areas.

5 Must Know Facts For Your Next Test

1. The trapezoidal rule approximates the integral by replacing the function with a series of straight-line segments, forming trapezoids between the x-axis and the function curve.
2. The trapezoidal rule is derived from the fact that the area of a trapezoid is given by the average of its parallel sides multiplied by the distance between them.
3. The trapezoidal rule is a second-order method, meaning its error term decreases quadratically as the number of subintervals increases.
4. The trapezoidal rule is commonly used in numerical integration because it is easy to implement and provides a reasonable balance between accuracy and computational efficiency.
5. The trapezoidal rule is often used in the context of the Fundamental Theorem of Calculus to approximate the area under a curve when the antiderivative is not known or difficult to compute.

Review Questions

• Explain how the trapezoidal rule is used to approximate the definite integral of a function.
  • The trapezoidal rule approximates the definite integral of a function by dividing the interval of integration into a number of subintervals and replacing the function with straight-line segments between the subinterval endpoints. The area under the function is then estimated by summing the areas of the trapezoids formed by these line segments. This provides a numerical approximation of the integral, which becomes more accurate as the number of subintervals is increased.
• Describe the relationship between the trapezoidal rule and the Fundamental Theorem of Calculus.
  • The Fundamental Theorem of Calculus establishes the connection between the definite integral of a function and its antiderivative. When the antiderivative is not known or difficult to compute, the trapezoidal rule can be used to numerically approximate the definite integral. This allows for the estimation of the area under the curve, which is a key application of the Fundamental Theorem of Calculus, even in cases where the analytical solution is not readily available.
• Analyze the advantages and limitations of the trapezoidal rule in the context of numerical integration compared to other methods, such as Simpson's rule.
  • The trapezoidal rule is a relatively simple and straightforward numerical integration method, making it easy to implement and computationally efficient. However, it is a second-order method, meaning its error decreases quadratically with the number of subintervals, whereas Simpson's rule is a fourth-order method with a faster error convergence. This means that Simpson's rule can often provide more accurate results than the trapezoidal rule, especially for functions with higher curvature. The choice between the trapezoidal rule and other numerical integration methods, such as Simpson's rule, depends on the specific problem, the desired level of accuracy, and the computational resources available.

Related terms

Numerical Integration:

The process of approximating the value of a definite integral using numerical methods, rather than analytical techniques.

Riemann Sum:

A method of approximating the definite integral of a function by dividing the interval into subintervals and summing the areas of the rectangles formed by the function values at the subinterval endpoints.

Simpson's Rule:

Another numerical integration method that uses parabolic approximations to estimate the definite integral, often more accurate than the trapezoidal rule.