Krista King Math | Online math help

View Original

Finding the Maclaurin series

Maclaurin series as the Taylor series centered around a=0

A Maclaurin series is the specific instance of the Taylor series when ???a=0???.

Remember that we can choose any value of ???a??? in order to find a Taylor polynomial. Maclaurin series eliminate that choice and force us to choose ???a=0???.

Remember that we would always use the formula

???\frac{f^{(n)}(a)}{n!}(x-a)^n???

to build each term in the Taylor series. Since ???a=0??? in every Maclaurin series, this formula simplifies to

???\frac{f^{(n)}(0)}{n!}(x-0)^n???

???\frac{f^{(n)}(0)}{n!}x^n???

Everything else about the Maclaurin series is the same.

How to build the Maclaurin series


Take the course

Want to learn more about Calculus 2? I have a step-by-step course for that. :)


Finding the nth-degree Maclaurin series

Example

Find the seventh-degree Maclaurin series of the function.

???f(x)=\sin{(3x)}???

We’ll start by creating the chart we’ve always made for Taylor polynomials. Since we’re finding the series to the seventh-degree, we’ll use ???n??? from ???0??? to ???7???. Since it’s a Maclaurin series, we’ll use ???a=0???.

With the whole chart filled in, we can build each term of the Maclaurin series.

Putting all of the terms together, we get the seventh-degree Maclaurin series.

???0+3x+0-\frac{27}{6}x^3+0+\frac{81}{40}x^5+0-\frac{243}{560}x^7???

???3x-\frac{27}{6}x^3+\frac{81}{40}x^5-\frac{243}{560}x^7???


Get access to the complete Calculus 2 course