Skip to main content
Ch. 1 - Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook
Chapter 1, Problem 34d

Find the largest interval on which the given function is increasing.


d. R(x) = √ 2x - 1

Verified step by step guidance
1
First, understand that a function is increasing on an interval if its derivative is positive on that interval. So, we need to find the derivative of the function R(x) = √(2x - 1).
To find the derivative, use the chain rule. The function can be rewritten as (2x - 1)^(1/2). The derivative of this function is (1/2)(2x - 1)^(-1/2) * (d/dx)(2x - 1).
Calculate the derivative of the inner function (2x - 1), which is simply 2. Therefore, the derivative of R(x) is (1/2)(2x - 1)^(-1/2) * 2.
Simplify the expression for the derivative: R'(x) = (2/2)(2x - 1)^(-1/2) = (2x - 1)^(-1/2).
Determine where the derivative is positive. Since (2x - 1)^(-1/2) is positive when 2x - 1 > 0, solve the inequality 2x - 1 > 0 to find the interval where the function is increasing.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1m
Was this helpful?

Key Concepts

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

Derivative

The derivative of a function measures the rate at which the function's value changes as its input changes. To determine where a function is increasing, we analyze its derivative: if the derivative is positive over an interval, the function is increasing on that interval.
Recommended video:
05:44
Derivatives

Critical Points

Critical points occur where the derivative of a function is zero or undefined. These points are essential for identifying intervals of increase or decrease, as they can indicate potential local maxima or minima, which help in determining the overall behavior of the function.
Recommended video:
04:50
Critical Points

Interval Notation

Interval notation is a mathematical notation used to represent a range of values. It is crucial for expressing the intervals on which a function is increasing or decreasing. For example, the interval (a, b) indicates that the function is increasing from point a to point b, not including the endpoints.
Recommended video:
04:22
Sigma Notation