You are Here: Home >< Maths

# Maclaurin series

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016
1. So the question is to determine the Maclaurin series up to term in x^3. I'm stuck on one particluar one. I keep feeling this has clicked then get set back.

(1 + x)*e^-x

So I have worked out the differentials
(1+x)*e^-x
-xe^-x
(x-1)*e^-x
-(x-2)*e^-x

Subbed in for when x = 0
1
-e^-1
e^-2
e^-1

And then put it into the formula for Maclaurin series but I am going wrong somewhere because it isn't the right answer. Any help is appreciated thanks. I don't know if i'm starting off wrong on this on or halfway....
2. (Original post by RHCPfan)
So the question is to determine the Maclaurin series up to term in x^3. I'm stuck on one particluar one. I keep feeling this has clicked then get set back.

(1 + x)*e^-x

So I have worked out the differentials
(1+x)*e^-x
-xe^-x
(x-1)*e^-x
-(x-2)*e^-x

Subbed in for when x = 0
1
-e^-1
e^-2
e^-1

And then put it into the formula for Maclaurin series but I am going wrong somewhere because it isn't the right answer. Any help is appreciated thanks. I don't know if i'm starting off wrong on this on or halfway....
Huh? Subbing in x = 0 you should get
1
0
-1
2
3. (Original post by RHCPfan)
So the question is to determine the Maclaurin series up to term in x^3. I'm stuck on one particluar one. I keep feeling this has clicked then get set back.

(1 + x)*e^-x

So I have worked out the differentials
(1+x)*e^-x
-xe^-x
(x-1)*e^-x
-(x-2)*e^-x

Subbed in for when x = 0
1
-e^-1
e^-2
e^-1

And then put it into the formula for Maclaurin series but I am going wrong somewhere because it isn't the right answer. Any help is appreciated thanks. I don't know if i'm starting off wrong on this on or halfway....

but when you sub in x=0, there shouldn't be any terms because
4. (Original post by 13 1 20 8 42)
Huh? Subbing in x = 0 you should get
1
0
-1
2
(Original post by RDKGames)

but when you sub in x=0, there shouldn't be any terms because
Oh man I've just seen where I have gone wrong! Thank you both!! Saying I was subbing x=0 when I was doing 0,1,2. It's been a long day haha.
5. (Original post by 13 1 20 8 42)
Huh? Subbing in x = 0 you should get
1
0
-1
2
(Original post by RDKGames)

but when you sub in x=0, there shouldn't be any terms because
Oh man I've just seen where I have gone wrong! Thank you both!! Saying I was subbing x=0 when I was doing 0,1,2. It's been a long day haha.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: August 12, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams