Please simplify this sigma question? [closed]
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I am not able to solve this sigma question. Please anybody solve this question by steps.
$$sum_R=1^Nleft(frac13right)^R-1$$
summation
closed as off-topic by Alex Francisco, TheGeekGreek, José Carlos Santos, Claude Leibovici, Gibbs Jul 18 at 9:16
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Alex Francisco, TheGeekGreek, José Carlos Santos, Claude Leibovici, Gibbs
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up vote
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I am not able to solve this sigma question. Please anybody solve this question by steps.
$$sum_R=1^Nleft(frac13right)^R-1$$
summation
closed as off-topic by Alex Francisco, TheGeekGreek, José Carlos Santos, Claude Leibovici, Gibbs Jul 18 at 9:16
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Alex Francisco, TheGeekGreek, José Carlos Santos, Claude Leibovici, Gibbs
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That's a geometric progression. Bad luck at Wimbledon!
– Lord Shark the Unknown
Jul 18 at 6:00
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up vote
-2
down vote
favorite
up vote
-2
down vote
favorite
I am not able to solve this sigma question. Please anybody solve this question by steps.
$$sum_R=1^Nleft(frac13right)^R-1$$
summation
I am not able to solve this sigma question. Please anybody solve this question by steps.
$$sum_R=1^Nleft(frac13right)^R-1$$
summation
edited Jul 18 at 6:01


Parcly Taxel
33.6k136588
33.6k136588
asked Jul 18 at 5:58


Rafael Nadal
1076
1076
closed as off-topic by Alex Francisco, TheGeekGreek, José Carlos Santos, Claude Leibovici, Gibbs Jul 18 at 9:16
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Alex Francisco, TheGeekGreek, José Carlos Santos, Claude Leibovici, Gibbs
closed as off-topic by Alex Francisco, TheGeekGreek, José Carlos Santos, Claude Leibovici, Gibbs Jul 18 at 9:16
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Alex Francisco, TheGeekGreek, José Carlos Santos, Claude Leibovici, Gibbs
3
That's a geometric progression. Bad luck at Wimbledon!
– Lord Shark the Unknown
Jul 18 at 6:00
add a comment |Â
3
That's a geometric progression. Bad luck at Wimbledon!
– Lord Shark the Unknown
Jul 18 at 6:00
3
3
That's a geometric progression. Bad luck at Wimbledon!
– Lord Shark the Unknown
Jul 18 at 6:00
That's a geometric progression. Bad luck at Wimbledon!
– Lord Shark the Unknown
Jul 18 at 6:00
add a comment |Â
1 Answer
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up vote
2
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accepted
Let $r=frac13$, and
$$S_N=sum_R=1^Nleft(frac13right)^R-1=sum_R=1^Nr^R-1$$
You have
$$rS_N=rsum_R=1^Nr^R-1=sum_R=1^Nr^R$$
Then
$$S(r-1)=rS-S=sum_R=1^Nr^R-sum_R=1^Nr^R-1=cdots=r^N-r^0$$
So
$$S=dfrac1-r^N1-r=frac32left(1-frac13^Nright)$$
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
accepted
Let $r=frac13$, and
$$S_N=sum_R=1^Nleft(frac13right)^R-1=sum_R=1^Nr^R-1$$
You have
$$rS_N=rsum_R=1^Nr^R-1=sum_R=1^Nr^R$$
Then
$$S(r-1)=rS-S=sum_R=1^Nr^R-sum_R=1^Nr^R-1=cdots=r^N-r^0$$
So
$$S=dfrac1-r^N1-r=frac32left(1-frac13^Nright)$$
add a comment |Â
up vote
2
down vote
accepted
Let $r=frac13$, and
$$S_N=sum_R=1^Nleft(frac13right)^R-1=sum_R=1^Nr^R-1$$
You have
$$rS_N=rsum_R=1^Nr^R-1=sum_R=1^Nr^R$$
Then
$$S(r-1)=rS-S=sum_R=1^Nr^R-sum_R=1^Nr^R-1=cdots=r^N-r^0$$
So
$$S=dfrac1-r^N1-r=frac32left(1-frac13^Nright)$$
add a comment |Â
up vote
2
down vote
accepted
up vote
2
down vote
accepted
Let $r=frac13$, and
$$S_N=sum_R=1^Nleft(frac13right)^R-1=sum_R=1^Nr^R-1$$
You have
$$rS_N=rsum_R=1^Nr^R-1=sum_R=1^Nr^R$$
Then
$$S(r-1)=rS-S=sum_R=1^Nr^R-sum_R=1^Nr^R-1=cdots=r^N-r^0$$
So
$$S=dfrac1-r^N1-r=frac32left(1-frac13^Nright)$$
Let $r=frac13$, and
$$S_N=sum_R=1^Nleft(frac13right)^R-1=sum_R=1^Nr^R-1$$
You have
$$rS_N=rsum_R=1^Nr^R-1=sum_R=1^Nr^R$$
Then
$$S(r-1)=rS-S=sum_R=1^Nr^R-sum_R=1^Nr^R-1=cdots=r^N-r^0$$
So
$$S=dfrac1-r^N1-r=frac32left(1-frac13^Nright)$$
answered Jul 18 at 6:17
Karn Watcharasupat
3,8192426
3,8192426
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add a comment |Â
3
That's a geometric progression. Bad luck at Wimbledon!
– Lord Shark the Unknown
Jul 18 at 6:00