Question

What is the 32nd term of the arithmetic sequence where a1 = 12 and a13 = -60?

Answer 1

a term in an arithmetic series can be found using

\[T_{n} = a_{1} + (n - 1)d\]

this can be used with the a13 and a1 to find the common difference (d)

\[-60 = 12 + (13 - 1)d ,,,, or ... -60 = 12 + 12d\]

solve for d

when you have d, you can find the 32 term by

\[T_{32} = 12 + (32 -1)d\]

Answer 2

So the answer would be -174?

Answer 3

what was d..?

Answer 4

-6

Answer 5

yep... so the answer is correct... well done.

Answer 6

Thanks!