Question

Write the sum using summation notation, assuming the suggested pattern continues. -9 - 4 + 1 + 6 + ... + 66

Answer 1

`\sum\limits^n_(k=1) {(-14+5k)}`

Explanation:

The series is an arithmetic series with first term (a1) -9 and common difference (d) 5. Then the general term (an) is ...

an = a1 +d(n-1) = -9 +5(n-1) = -14 +5n

The summation notation indicates the sum of "n" of these terms.