Question

100 + 95 + 90 + 85 summation notation series solution

Answer 1

Since we are decreasing by 5 each time, we can build up a series formula first.

`S_n = (n)/(2)(2a + (n - 1)d)`

`S_n = (n)/(2)(200 - 5(n - 1))`

Now, adding summation notation, we produce:


`\sum_(k = 1)^(n)[(k)/(2)(200 - 5(k - 1))]`