What is the 4th term of the summation sum_r=36 (2r+3)?

Question

ScanSolve AI Tutor · Accepted Answer

Here's how to find the 4th term of the summation:

Identify the starting value of the index and the expression for each term.
The summation is $\sum_{r=3}^{6} (2r+3)$ .
The index $r$ starts at 3. The expression for each term is $2r+3$ .
Determine the value of $r$ that corresponds to the 4th term.
The terms are generated by incrementing $r$ from its starting value.
- The 1st term occurs when $r=3$ .
- The 2nd term occurs when $r=4$ .
- The 3rd term occurs when $r=5$ .
- The 4th term occurs when $r=6$ .
Substitute the value of $r$ for the 4th term into the expression.
For the 4th term, $r=6$ .
$2r+3 = 2(6) + 3$ $= 12 + 3$ $= 15$
The 4th term is $\boxed{15}$ .

Answer