#Turning recursive sequence into an explicit sequence
28 messages · Page 1 of 1 (latest)
Bunjeet
<@&286206848099549185>
Can you share the actual question? You should always share the original question, by the way.
@night jacinth this is basically the whole question, apart from where the question says to prove the sequence is increasing
i understand to do that i need to do induction
but from what i understand i need to turn this recursive formula into an explicit one in order to be able to do that induction
that is the part i am stuck on
<@&286206848099549185>
Just share a picture of the original question
What you think is irrelevant might not be irrelevant to us
If you only need to prove that the sequence is increasing then you don’t need an explicit sequence
You can do that with induction
Prove that $x_{n+1}>x_n \Rightarrow x_{n+2}>x_{n+1}$
FirstNameLastName
@quaint axle Sorry i dont have the exact question written out properly, just in hand notes, but yes i just have to show that the sequence is increasing and give an upper bound. So, with what you have said here, if i prove x_x+2>xn+1 does it then imply x_n+1 >xn or no?
how would i prove x_n+1>x_n if i dont know what x_n is
thanks for helping aswell
If you gonna do this by Induction you don't need to know x_n.
Just begin by showing that for the smallest n = 1 the inequality is true.
Then after you found at least one n ∈ ℕ that makes xₙ₊₁ > xₙ true.
This will be your precondition for your Induction. (1).
∃ n ∈ ℕ : xₙ₊₁ > xₙ (1)
Now the second step is as already mentioned above to show it for n -> n+1.
In other terms:
Prove $x_{n+2}>x_{n+1}$
You need to transform the inequality in such a way where you can use your Induction assumption (1). By doing that you completed the proof then.
adoniszgks