Skip to main content
Ch. 7 - Logarithmic, Exponential Functions, and Hyperbolic Functions
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Not the one you use?Change textbook
Chapter 7, Problem 7.3.79a

Evaluating hyperbolic functions Evaluate each expression without using a calculator or state that the value does not exist. Simplify answers as much as possible.


a. cosh 0

Verified step by step guidance
1
Recall the definition of the hyperbolic cosine function: \(\cosh x = \frac{e^{x} + e^{-x}}{2}\).
Substitute \(x = 0\) into the definition: \(\cosh 0 = \frac{e^{0} + e^{-0}}{2}\).
Evaluate the exponentials: \(e^{0} = 1\) and \(e^{-0} = 1\).
Add the values in the numerator: \(1 + 1 = 2\).
Divide by 2 to simplify: \(\cosh 0 = \frac{2}{2}\).

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.

Definition of Hyperbolic Cosine (cosh)

The hyperbolic cosine function, cosh(x), is defined as (e^x + e^(-x)) / 2. It is an even function and describes the shape of a hanging cable or chain (catenary). Understanding this definition allows direct evaluation of cosh at any point, including zero.
Recommended video:
05:43
Definition of the Definite Integral

Properties of Exponential Functions

Exponential functions e^x and e^(-x) are fundamental in defining hyperbolic functions. Knowing that e^0 = 1 simplifies calculations, especially when evaluating cosh(0), since it involves e^0 and e^(-0). This property helps in simplifying expressions without a calculator.
Recommended video:
06:21
Properties of Functions

Evaluating Functions at Specific Points

Evaluating a function at a specific point means substituting the value into the function's formula and simplifying. For cosh(0), substituting x=0 into the definition and simplifying using known values of exponentials yields the exact result without approximation.
Recommended video:
4:26
Evaluating Composed Functions