Question

Using the first three terms of the Maclaurin's series, what is the value of cos(Ï€/2)?

Answer 1

Do you know how to find the MacLaurin/Taylor series of cos(x)?

Answer 2

No!!

Answer 3

Here's the general form:

MacLaurin series of f(x) centered about x=0:
\[f(0) + f'(0)*x + \frac{f''(0)*x^2}{2!} + \frac{f'''(0)*x^3}{3!} + ... + \frac{f^n(0)*x^n}{n!} + ...\] Use this to find the MacLaurin series of cos(x). You should notice a pattern pretty quickly, and since you're only using the first three terms, you want to plug π/2 for x after you get the series.

Answer 4

Thank you !!

Answer 5

Sorry, the general term should be f^(n) instead of f^n, because you're taking the n-th derivative of the function at 0. No problem. :)

Answer 6

O.K.