
Let

denote the

th partial sum of the series, i.e.

Then

and subtracting from

we get


As

, the exponential term vanishes, leaving us with

and so
X y
4 650
7 575
11 475
there ya go ^^
Remember when solving inequalities the sign of your inequality reverses when dividing or multiplying negative values. k/-12<15. k>-180 [-180, positive infinity)