# Taylor Polynomial

1. Oct 18, 2009

### Newbatmath

Hey guys! I am attempting to do this problem and have been working with it for awhile now. Once again, it is an issue of the textbook not being very clear and making me more confused than ever. Sadly, our teacher is still MIA.

Find the third Taylor polynomial P3(x) for the function f(x)= (x-1)In(x) , about x0 = 1; and use p3(0.5) to approx. f(0.5). Find the upper bound for error /f(0.5) – p3(0.5)/, then compare it to the actual error.

I know this is a tall order but any help you could give me that I could compare to my work here would be such a help! Thanks a bunch!

2. Oct 18, 2009

### whs

What is the 'In(x)' in your function. Do you mean 'ln(x)'?

Otherwise this question is very straightforward. Just calculate the first 3rd Taylor polynomial and plug in numbers.

I don't see the problem?

3. Oct 18, 2009

### Newbatmath

Yep, you are right. ln(x). Sorry about that. :) Thanks so much!

4. Oct 18, 2009

### Newbatmath

Okay so I somehow got -4.25. Does anyone else think that is correct?

Anyone know how to find the actual error?