I've looked it up on Google, and found out how to find missing numbers given a certain arithmetic sequence where numbers are increasing by the same number each time (ex. 5..10..15..20..25..)
However, what I can't seem to understand is how to figure it out if the number it increases by switches off (ex. 1..6..12..17..23..) +5, +6, +5 etc.
So, if a question were to ask, What is the 101st term in the arithmetic sequence 9..15..20..26..31..37..42? How would I solve that?
However, what I can't seem to understand is how to figure it out if the number it increases by switches off (ex. 1..6..12..17..23..) +5, +6, +5 etc.
So, if a question were to ask, What is the 101st term in the arithmetic sequence 9..15..20..26..31..37..42? How would I solve that?
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What is the 101st term in the arithmetic sequence 9..15..20..26..31..37..42?
Just consider the odd terms.
For odd terms only
nth term = 9+(n-1)*11/2 = (11n+7)/2
101st term = (11*101+7)/2 = 559
Just consider the odd terms.
For odd terms only
nth term = 9+(n-1)*11/2 = (11n+7)/2
101st term = (11*101+7)/2 = 559
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If it alternates, then think of it as a sequence that adds the two alternating guys together.
In your example, you have:
1,6,12,17,...
Observe the subsequence: 1 + (5+6) = 12
12 + (5+6) = 23 etc.
In your example, you have:
1,6,12,17,...
Observe the subsequence: 1 + (5+6) = 12
12 + (5+6) = 23 etc.