Question

Evaluate the geometric series below. Please show your work.

Answer 1

-1310715

Explanation:

By the formula of a geometric sequence, we work out:

`\sum_(k=1)^(18) -5 \cdot 2^(k-1)\\= -5 \cdot \sum_(k=0)^(17) 2^(k)\\= -5 \cdot (2^(18)-1)/(2-1)\\= -1310715`