Question

MedaL FOR HELP :)
Tell whether the sequence is arithmetic.If it is what is the common defference ?
2,7,13,20....
A.Yes 5
b. yes 6
c.yes 7
d.no

Answer 1

My answer is a

Answer 2

d

Answer 3

so D.

Answer 4

wow ok no D ty

Answer 5

No, this is not an arithmetic sequence. This is a special triangular sequence. Each term us defined by (n^2 +n)/2.

The difference between the numbers are not the same btw.

I suggest this link, look under the special triangle section for formula and example of this problem type of sequence.

http://www.fibonicci.com/math/number-sequences/examples-types/