Strategy of drawing the points of the sequence

AI Thread Summary
The discussion focuses on strategies for finding the general term of a sequence, with an emphasis on drawing points to visualize the sequence. While some sequences, like simple counting numbers, are easy to identify, others, such as the Fibonacci sequence, require more observation and time. Participants share that while there are limited tricks, recognizing patterns like alternating signs can be helpful. One user notes they eventually found the general term through observation but seeks more efficient methods. Overall, the conversation highlights the challenge of identifying sequence patterns and the need for effective strategies.
PPonte
I started the study of sequences some days ago and I am searching for tricks, hints, that could help me find the general term of a sequence. I am following the strategy of drawing the points of the sequence and then I try to find the expression of a function that contains those points. But, unfortunately, this is not helping me with the sequence I am dealing with right now. Would you please tell me your strategies/tricks?

Thank you. :wink:
 
Physics news on Phys.org
Much of the time it depends on the actual sequence. For example, the sequence 1, 2, 3, 4, 5...is easy to see by observation, but the sequence 1, 1, 2, 3, 5... (Fibonnaci) isn't as easy by inspection.
 
Thank you, daveb, altough I already knew that. I ended up finding the general term of the sequence I was dealing with, precisely, by observation. But it takes time, I need tricks :).
 
The ultimate trick : http://www.research.att.com/~njas/sequences/
 
Last edited by a moderator:
...interesting. But during a test I cannot use this trick :) .
 
I don't think there are too many tricks, but I would try to remember that

<br /> (-1)^{n} = 1, -1, 1, -1, 1...<br />

and

<br /> (-1)^{n+1} = -1, 1, -1, 1, -1...<br />
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks
Since ##px^9+q## is the factor, then ##x^9=\frac{-q}{p}## will be one of the roots. Let ##f(x)=27x^{18}+bx^9+70##, then: $$27\left(\frac{-q}{p}\right)^2+b\left(\frac{-q}{p}\right)+70=0$$ $$b=27 \frac{q}{p}+70 \frac{p}{q}$$ $$b=\frac{27q^2+70p^2}{pq}$$ From this expression, it looks like there is no greatest value of ##b## because increasing the value of ##p## and ##q## will also increase the value of ##b##. How to find the greatest value of ##b##? Thanks

Similar threads

Replies
1
Views
2K
Replies
7
Views
2K
Replies
24
Views
2K
Replies
2
Views
2K
Replies
17
Views
3K
Replies
16
Views
3K
Replies
1
Views
2K
Replies
10
Views
2K
Back
Top