Question

Write the sum using summation notation, assuming the suggested pattern continues.

-9 - 4 + 1 + 6 + ... + 66

Answer 1

Is this the problem you need help with?

Answer 2

yes

Answer 3

so

Answer 4

Since this is an arithmetic sequence and the common difference between each term is 5, we can use this formula, \[\sum_{k = 0}^{ n -1} (a+kd) = \frac{ n }{ 2 }(2a + (n -1)d)\] to find out what term 66 is.

Answer 5

can you tell me the answer