Sum of $n$ terms of the series $frac 1(1 + x)(1 +2x) + frac 1(1 +2x)(1 +3x) + ldots$ is equal to?

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My try : By using Vn Method 
But the answer is $frac n(1+x)(1+ (n+1)x)$
Please tell me where I am wrong or what is the correct method to solve it.
Thanks
sequences-and-series
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up vote
0
down vote
favorite
My try : By using Vn Method 
But the answer is $frac n(1+x)(1+ (n+1)x)$
Please tell me where I am wrong or what is the correct method to solve it.
Thanks
sequences-and-series
Please rotate photograph.
â Mohammad Zuhair Khan
Sep 8 at 5:03
3
The general term should be $frac1(1+nx)[1+(n+1)x]$ instead of $frac1(1+nx)(1+2nx)$
â Yuta
Sep 8 at 5:10
add a comment |Â
up vote
0
down vote
favorite
up vote
0
down vote
favorite
My try : By using Vn Method 
But the answer is $frac n(1+x)(1+ (n+1)x)$
Please tell me where I am wrong or what is the correct method to solve it.
Thanks
sequences-and-series
My try : By using Vn Method 
But the answer is $frac n(1+x)(1+ (n+1)x)$
Please tell me where I am wrong or what is the correct method to solve it.
Thanks
sequences-and-series
sequences-and-series
edited Sep 8 at 5:30
Mohammad Zuhair Khan
968422
968422
asked Sep 8 at 5:00
user580093
8815
8815
Please rotate photograph.
â Mohammad Zuhair Khan
Sep 8 at 5:03
3
The general term should be $frac1(1+nx)[1+(n+1)x]$ instead of $frac1(1+nx)(1+2nx)$
â Yuta
Sep 8 at 5:10
add a comment |Â
Please rotate photograph.
â Mohammad Zuhair Khan
Sep 8 at 5:03
3
The general term should be $frac1(1+nx)[1+(n+1)x]$ instead of $frac1(1+nx)(1+2nx)$
â Yuta
Sep 8 at 5:10
Please rotate photograph.
â Mohammad Zuhair Khan
Sep 8 at 5:03
Please rotate photograph.
â Mohammad Zuhair Khan
Sep 8 at 5:03
3
3
The general term should be $frac1(1+nx)[1+(n+1)x]$ instead of $frac1(1+nx)(1+2nx)$
â Yuta
Sep 8 at 5:10
The general term should be $frac1(1+nx)[1+(n+1)x]$ instead of $frac1(1+nx)(1+2nx)$
â Yuta
Sep 8 at 5:10
add a comment |Â
1 Answer
1
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2
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accepted
I am sorry but, being almost blind, I am unable to read your photograph.
Considering $$a_n=frac n(1+x)(1+ (n+1)x)$$ use patrial fraction decomposition to get
$$a_n=fracn+1(n+1) x+1-fracnn x+1$$ which beautifully telescopes.
I am sure that you can take it from here.
Yeah , thanks understood the concept , sorry for the bad picture
â user580093
Sep 8 at 5:35
@user580093. You are welcome ! On this site, if I may suggest, use MathJax for typing; it is quite easy and you will probably get more answers than when posting photographs. Cheers.
â Claude Leibovici
Sep 8 at 5:46
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
accepted
I am sorry but, being almost blind, I am unable to read your photograph.
Considering $$a_n=frac n(1+x)(1+ (n+1)x)$$ use patrial fraction decomposition to get
$$a_n=fracn+1(n+1) x+1-fracnn x+1$$ which beautifully telescopes.
I am sure that you can take it from here.
Yeah , thanks understood the concept , sorry for the bad picture
â user580093
Sep 8 at 5:35
@user580093. You are welcome ! On this site, if I may suggest, use MathJax for typing; it is quite easy and you will probably get more answers than when posting photographs. Cheers.
â Claude Leibovici
Sep 8 at 5:46
add a comment |Â
up vote
2
down vote
accepted
I am sorry but, being almost blind, I am unable to read your photograph.
Considering $$a_n=frac n(1+x)(1+ (n+1)x)$$ use patrial fraction decomposition to get
$$a_n=fracn+1(n+1) x+1-fracnn x+1$$ which beautifully telescopes.
I am sure that you can take it from here.
Yeah , thanks understood the concept , sorry for the bad picture
â user580093
Sep 8 at 5:35
@user580093. You are welcome ! On this site, if I may suggest, use MathJax for typing; it is quite easy and you will probably get more answers than when posting photographs. Cheers.
â Claude Leibovici
Sep 8 at 5:46
add a comment |Â
up vote
2
down vote
accepted
up vote
2
down vote
accepted
I am sorry but, being almost blind, I am unable to read your photograph.
Considering $$a_n=frac n(1+x)(1+ (n+1)x)$$ use patrial fraction decomposition to get
$$a_n=fracn+1(n+1) x+1-fracnn x+1$$ which beautifully telescopes.
I am sure that you can take it from here.
I am sorry but, being almost blind, I am unable to read your photograph.
Considering $$a_n=frac n(1+x)(1+ (n+1)x)$$ use patrial fraction decomposition to get
$$a_n=fracn+1(n+1) x+1-fracnn x+1$$ which beautifully telescopes.
I am sure that you can take it from here.
answered Sep 8 at 5:34
Claude Leibovici
113k1155127
113k1155127
Yeah , thanks understood the concept , sorry for the bad picture
â user580093
Sep 8 at 5:35
@user580093. You are welcome ! On this site, if I may suggest, use MathJax for typing; it is quite easy and you will probably get more answers than when posting photographs. Cheers.
â Claude Leibovici
Sep 8 at 5:46
add a comment |Â
Yeah , thanks understood the concept , sorry for the bad picture
â user580093
Sep 8 at 5:35
@user580093. You are welcome ! On this site, if I may suggest, use MathJax for typing; it is quite easy and you will probably get more answers than when posting photographs. Cheers.
â Claude Leibovici
Sep 8 at 5:46
Yeah , thanks understood the concept , sorry for the bad picture
â user580093
Sep 8 at 5:35
Yeah , thanks understood the concept , sorry for the bad picture
â user580093
Sep 8 at 5:35
@user580093. You are welcome ! On this site, if I may suggest, use MathJax for typing; it is quite easy and you will probably get more answers than when posting photographs. Cheers.
â Claude Leibovici
Sep 8 at 5:46
@user580093. You are welcome ! On this site, if I may suggest, use MathJax for typing; it is quite easy and you will probably get more answers than when posting photographs. Cheers.
â Claude Leibovici
Sep 8 at 5:46
add a comment |Â
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Please rotate photograph.
â Mohammad Zuhair Khan
Sep 8 at 5:03
3
The general term should be $frac1(1+nx)[1+(n+1)x]$ instead of $frac1(1+nx)(1+2nx)$
â Yuta
Sep 8 at 5:10