I have the following sequence to work out -
1, 7, 25, 63, 129, 231
First line of differences = 6, 18, 38, 66, 102
Second line = 12, 20, 28, 26
Third line = 8, 8, 8
The formula for this is t=an^3 x bn^2 x cn x d
Where t=the total number of cubes in the term
For a quadratic sequence, a = half the second difference (I am assuming that for a cubic sequence, it is half the third difference)
c = 0th term (but how can I work out the 0th term for a cubic sequence, surely d must = the 0th term, but then what does c equal?
And what is d equal to in a cubic sequence?
PS if it helps, I am trying to do 3d borders coursework, and I can't ask my teacher because it's in in the morning!
2007-03-25
02:42:52
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2 answers
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asked by
Helena
6
in
Mathematics