Write the sum in sigma notation 72 + 61 + 50 + 39 +...+ -104 ??

sum_(k=1)^AB

I'm given; "The answer for A should be a number and the answer for B should be an expression."

1 Answer
Jun 26, 2018

Shown below

Explanation:

Here the k^"th" term is -11k + 83

So the first term, at k=1 is 72 and the final term is -104

Hence -11k + 83 = -104 => k = 17

Hence we are summing up from k=1 to k = 17 of -11k + 83

Hence sum_(k=1) ^17 (-11k +83)