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# Maclaurin series watch

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.

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