The limit of a sequence $u_n+1=exp(u_n)+u_n$ [closed]
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Please help me to find the limit of this sequence :
$ u_0=-2017;$ and $; u_n+1 =e^u_n+u_n $
I don't know if the limit exist or not.
sequences-and-series recurrence-relations
closed as off-topic by amWhy, José Carlos Santos, Shailesh, Alan Wang, Parcly Taxel Jul 19 at 1:10
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." – amWhy, José Carlos Santos, Shailesh, Alan Wang, Parcly Taxel
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up vote
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Please help me to find the limit of this sequence :
$ u_0=-2017;$ and $; u_n+1 =e^u_n+u_n $
I don't know if the limit exist or not.
sequences-and-series recurrence-relations
closed as off-topic by amWhy, José Carlos Santos, Shailesh, Alan Wang, Parcly Taxel Jul 19 at 1:10
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." – amWhy, José Carlos Santos, Shailesh, Alan Wang, Parcly Taxel
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HINT: $$u_n+1-u_n = e^u_n>0$$ implies that the sequence is strictly increasing. Thus the limit necessarily exists (possibly $+ infty$). Now, $$u_n+1-u_0= sum_k=0^n e^u_k > sum_k=0^n e^u_0 = u_0 cdot (n+1) to infty$$
– Crostul
Jul 18 at 20:08
Hmm... raises the question of whether it's "converges to infinity" or "diverges to infinity".
– Robert Wolfe
Jul 18 at 20:09
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up vote
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Please help me to find the limit of this sequence :
$ u_0=-2017;$ and $; u_n+1 =e^u_n+u_n $
I don't know if the limit exist or not.
sequences-and-series recurrence-relations
Please help me to find the limit of this sequence :
$ u_0=-2017;$ and $; u_n+1 =e^u_n+u_n $
I don't know if the limit exist or not.
sequences-and-series recurrence-relations
edited Jul 18 at 20:07


amWhy
189k25219431
189k25219431
asked Jul 18 at 20:02
user574907
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closed as off-topic by amWhy, José Carlos Santos, Shailesh, Alan Wang, Parcly Taxel Jul 19 at 1:10
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." – amWhy, José Carlos Santos, Shailesh, Alan Wang, Parcly Taxel
closed as off-topic by amWhy, José Carlos Santos, Shailesh, Alan Wang, Parcly Taxel Jul 19 at 1:10
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." – amWhy, José Carlos Santos, Shailesh, Alan Wang, Parcly Taxel
1
HINT: $$u_n+1-u_n = e^u_n>0$$ implies that the sequence is strictly increasing. Thus the limit necessarily exists (possibly $+ infty$). Now, $$u_n+1-u_0= sum_k=0^n e^u_k > sum_k=0^n e^u_0 = u_0 cdot (n+1) to infty$$
– Crostul
Jul 18 at 20:08
Hmm... raises the question of whether it's "converges to infinity" or "diverges to infinity".
– Robert Wolfe
Jul 18 at 20:09
add a comment |Â
1
HINT: $$u_n+1-u_n = e^u_n>0$$ implies that the sequence is strictly increasing. Thus the limit necessarily exists (possibly $+ infty$). Now, $$u_n+1-u_0= sum_k=0^n e^u_k > sum_k=0^n e^u_0 = u_0 cdot (n+1) to infty$$
– Crostul
Jul 18 at 20:08
Hmm... raises the question of whether it's "converges to infinity" or "diverges to infinity".
– Robert Wolfe
Jul 18 at 20:09
1
1
HINT: $$u_n+1-u_n = e^u_n>0$$ implies that the sequence is strictly increasing. Thus the limit necessarily exists (possibly $+ infty$). Now, $$u_n+1-u_0= sum_k=0^n e^u_k > sum_k=0^n e^u_0 = u_0 cdot (n+1) to infty$$
– Crostul
Jul 18 at 20:08
HINT: $$u_n+1-u_n = e^u_n>0$$ implies that the sequence is strictly increasing. Thus the limit necessarily exists (possibly $+ infty$). Now, $$u_n+1-u_0= sum_k=0^n e^u_k > sum_k=0^n e^u_0 = u_0 cdot (n+1) to infty$$
– Crostul
Jul 18 at 20:08
Hmm... raises the question of whether it's "converges to infinity" or "diverges to infinity".
– Robert Wolfe
Jul 18 at 20:09
Hmm... raises the question of whether it's "converges to infinity" or "diverges to infinity".
– Robert Wolfe
Jul 18 at 20:09
add a comment |Â
1 Answer
1
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up vote
10
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If the limit $l$ exists, $l=e^l+l$ implies $e^l=0$ impossible.
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
10
down vote
accepted
If the limit $l$ exists, $l=e^l+l$ implies $e^l=0$ impossible.
add a comment |Â
up vote
10
down vote
accepted
If the limit $l$ exists, $l=e^l+l$ implies $e^l=0$ impossible.
add a comment |Â
up vote
10
down vote
accepted
up vote
10
down vote
accepted
If the limit $l$ exists, $l=e^l+l$ implies $e^l=0$ impossible.
If the limit $l$ exists, $l=e^l+l$ implies $e^l=0$ impossible.
answered Jul 18 at 20:08


Tsemo Aristide
51.2k11243
51.2k11243
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add a comment |Â
1
HINT: $$u_n+1-u_n = e^u_n>0$$ implies that the sequence is strictly increasing. Thus the limit necessarily exists (possibly $+ infty$). Now, $$u_n+1-u_0= sum_k=0^n e^u_k > sum_k=0^n e^u_0 = u_0 cdot (n+1) to infty$$
– Crostul
Jul 18 at 20:08
Hmm... raises the question of whether it's "converges to infinity" or "diverges to infinity".
– Robert Wolfe
Jul 18 at 20:09