- #1

pat666

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## Homework Statement

Use the first two terms of the Maclaurin series expansion of cos(x) to solve the equation cos(x)-2x

^{2}=0 . Check its accuracy with a calculator ( is in radians).

## Homework Equations

f(x)=f(0)+x(f'(0)) first two terms

## The Attempt at a Solution

So I have found the Maclaurin expansion of cos(x) to be 1. This seems ridiculous to me so I'm wondering if its correct?

then:

1-2x

^{2}=0 so x=+-(sqrt(2)/2)

=+-.239755

I'm not sure what to say about the accuracy??

FYI this is an exam practice Q

Thanks