Question

Find the sum of the sequelle
Σ (k3 - 6)
k= 1
3
Σ (3-6) =

Answer 1

`\sum\limits^3_(k=1)(k^3 - 6) = 18`

Explanation:

Given

`\sum\limits^3_(k=1)(k^3 - 6)`

Required

Evaluate

This means that we substitute 1 to 3 for k.

So, we have:

`\sum\limits^3_(k=1)(k^3 - 6) = (1^3 - 6)+(2^3 - 6)+(3^3 - 6)`

`\sum\limits^3_(k=1)(k^3 - 6) = (1 - 6)+(8 - 6)+(27 - 6)`

`\sum\limits^3_(k=1)(k^3 - 6) = -5+2+21`

`\sum\limits^3_(k=1)(k^3 - 6) = 18`