Skip to main content
Ch. 6 - Applications of Integration
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Not the one you use?Change textbook
Chapter 6, Problem 6.4.72a

Explain the steps required to find the length of a curve x = g(y) between y=c and y=d.

Verified step by step guidance
1
Identify the function given as \(x = g(y)\) and the interval over which you want to find the curve length, from \(y = c\) to \(y = d\).
Recall the formula for the length of a curve expressed as \(x = g(y)\), which is given by the integral: \[L = \int_{c}^{d} \sqrt{1 + \left(\frac{dx}{dy}\right)^2} \, dy\]
Compute the derivative \(\frac{dx}{dy}\) by differentiating \(g(y)\) with respect to \(y\).
Substitute \(\frac{dx}{dy}\) into the integral formula to get: \[L = \int_{c}^{d} \sqrt{1 + \left(g'(y)\right)^2} \, dy\]
Evaluate the integral over the interval \([c, d]\) to find the length of the curve.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Arc Length Formula for Parametric Curves

The arc length of a curve defined by x = g(y) between y = c and y = d is found by integrating the square root of 1 plus the derivative of x with respect to y squared. This formula accounts for the infinitesimal distances along the curve, summing them to find the total length.
Recommended video:
06:29
Arc Length of Parametric Curves

Derivative of the Function x = g(y)

To apply the arc length formula, you need the derivative dx/dy, which measures how x changes with respect to y. This derivative is essential because it determines the slope of the curve and influences the length calculation by affecting the integrand.
Recommended video:
04:56
Derivative of the Natural Exponential Function (e^x)

Definite Integration over the Interval [c, d]

After setting up the integrand involving the derivative, you compute the definite integral from y = c to y = d. This integration sums the infinitesimal arc lengths along the curve, yielding the total length between the specified bounds.
Recommended video:
05:43
Definition of the Definite Integral