Skip to main content
Ch. 11 - Power Series
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Not the one you use?Change textbook
Chapter 11, Problem 11.3.43

Manipulating Taylor series Use the Taylor series in Table 11.5 to find the first four nonzero terms of the Taylor series for the following functions centered at 0.


sinh x²

Verified step by step guidance
1
Recall the Taylor series expansion for the hyperbolic sine function centered at 0: \(\sinh x = \sum_{n=0}^{\infty} \frac{x^{2n+1}}{(2n+1)!} = x + \frac{x^3}{3!} + \frac{x^5}{5!} + \frac{x^7}{7!} + \cdots\).
To find the Taylor series for \(\sinh(x^2)\), substitute \(x^2\) in place of \(x\) in the series for \(\sinh x\). This gives: \(\sinh(x^2) = \sum_{n=0}^{\infty} \frac{(x^2)^{2n+1}}{(2n+1)!} = \sum_{n=0}^{\infty} \frac{x^{4n+2}}{(2n+1)!}\).
Write out the first four nonzero terms explicitly by plugging in \(n=0,1,2,3\) into the series: \(\frac{x^{2}}{1!} + \frac{x^{6}}{3!} + \frac{x^{10}}{5!} + \frac{x^{14}}{7!}\).
Simplify the factorials in the denominators where possible: \(1! = 1\), \(3! = 6\), \(5! = 120\), \(7! = 5040\).
Express the first four nonzero terms of the Taylor series for \(\sinh(x^2)\) as: \(x^{2} + \frac{x^{6}}{6} + \frac{x^{10}}{120} + \frac{x^{14}}{5040} + \cdots\).

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.

Taylor Series Expansion

A Taylor series represents a function as an infinite sum of terms calculated from the derivatives at a single point, usually centered at zero (Maclaurin series). It approximates functions using polynomials, making complex functions easier to analyze and compute.
Recommended video:
08:42
Taylor Series

Hyperbolic Sine Function (sinh x)

The hyperbolic sine function, sinh x, is defined as (e^x - e^(-x))/2. Its Taylor series expansion at zero includes only odd powers of x with alternating signs, which helps in constructing series for related functions like sinh(x²).
Recommended video:
5:53
Graph of Sine and Cosine Function

Substitution in Series Expansions

Substitution involves replacing the variable in a known Taylor series with another expression, such as x², to find the series of composite functions. This technique allows leveraging existing expansions to find new series efficiently.
Recommended video:
06:00
Geometric Series