Skip to main content
Ch. 5 - Integrals
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook
Chapter 5, Problem 5.PE.17

Find the areas of the regions enclosed by the curves and lines in Exercises 15–26.
√x + √y = 1, x = 0, y = 0
Graph showing the region bounded by the curve √x + √y = 1 and the x and y axes, shaded in blue.

Verified step by step guidance
1
Rewrite the given curve equation \(\sqrt{x} + \sqrt{y} = 1\) to express \(y\) in terms of \(x\). Start by isolating \(\sqrt{y}\): \(\sqrt{y} = 1 - \sqrt{x}\).
Square both sides to solve for \(y\): \(y = (1 - \sqrt{x})^2 = 1 - 2\sqrt{x} + x\).
Identify the region bounded by the curve and the coordinate axes: \(x=0\), \(y=0\), and the curve \(y = (1 - \sqrt{x})^2\) from \(x=0\) to \(x=1\).
Set up the integral for the area of the region as \(\int_0^1 y \, dx = \int_0^1 (1 - 2\sqrt{x} + x) \, dx\).
Evaluate the integral step-by-step (without calculating the final value): integrate each term separately: \(\int_0^1 1 \, dx\), \(\int_0^1 -2\sqrt{x} \, dx\), and \(\int_0^1 x \, dx\), then sum the results to find the total area.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
3m
Was this helpful?

Key Concepts

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

Area Between Curves

The area between curves is found by integrating the difference between the upper and lower functions over a given interval. When bounded by axes and a curve, the area can be computed by setting up an integral with appropriate limits reflecting the region.
Recommended video:
05:23
Finding Area Between Curves on a Given Interval

Implicit Functions and Curve Manipulation

The given curve √x + √y = 1 is implicit. To find the area, it is often necessary to express y as a function of x or vice versa. This involves isolating one variable and squaring both sides carefully to avoid extraneous solutions.
Recommended video:
05:14
Finding The Implicit Derivative

Definite Integration with Variable Substitution

Calculating the area under curves involving roots often requires substitution to simplify the integral. For example, substituting u = √x or v = √y can transform the integral into a more manageable form, facilitating evaluation.
Recommended video:
04:27
Substitution With an Extra Variable