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 1.12

In Exercises 9–16, determine whether the function is even, odd, or neither.


𝔂 = sec x tan x

Verified step by step guidance
1
First, recall the definitions of even and odd functions. A function f(x) is even if f(-x) = f(x) for all x in the domain, and it is odd if f(-x) = -f(x) for all x in the domain.
To determine if the function y = sec(x) tan(x) is even, odd, or neither, we need to evaluate y(-x) and compare it to y(x).
Calculate y(-x): Substitute -x into the function to get y(-x) = sec(-x) tan(-x).
Use the trigonometric identities: sec(-x) = sec(x) and tan(-x) = -tan(x). Substitute these into y(-x) to get y(-x) = sec(x) (-tan(x)).
Compare y(-x) = sec(x) (-tan(x)) with y(x) = sec(x) tan(x). Since y(-x) = -y(x), the function y = sec(x) tan(x) is odd.

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.

Even and Odd Functions

A function is classified as even if it satisfies the condition f(-x) = f(x) for all x in its domain, meaning its graph is symmetric about the y-axis. Conversely, a function is odd if it meets the condition f(-x) = -f(x), indicating symmetry about the origin. Understanding these definitions is crucial for determining the nature of the given function.
Recommended video:
06:21
Properties of Functions

Trigonometric Functions

The function in question, 𝔶 = sec x tan x, involves trigonometric functions. The secant function, sec x, is defined as 1/cos x, and the tangent function, tan x, is defined as sin x/cos x. Familiarity with the properties and behaviors of these functions is essential for analyzing their symmetry.
Recommended video:
6:04
Introduction to Trigonometric Functions

Function Composition and Transformation

To determine if the function is even or odd, one must evaluate the function at -x, which involves substituting -x into the function and simplifying. This process of function composition and transformation is key to analyzing the symmetry properties of the function, allowing for a clear conclusion about its classification.
Recommended video:
5:25
Intro to Transformations