Question

Write the sum using summation notation.

2 + 5 + 8 + 11 + ... + 29

Also, I know that it is going up by 3 units. But I am not sure how to get it into the form below:

example:

15
‡” k +3
k-1

Answer 1

you know the "formula" has to be 3n -1 to make it start at 2 when n=1
what must be n when 3n-1 = 29?
3n = 30
n = 10

so , (don't know how to make summation sign)

summation of 3n-1, n=1 at the bottom, 10 at the top of the sign.