$\"\"$

The series is $\"\"$ .

The sum function is $\"\"$ .

$\"\"$ .

$\"\"$

Graph :

(1) Draw the coordinate plane.

(2) Graph the function $\"\"$ .

(3) Graph the first several parts of the sum of series.

$\"\"$ .

Observe the graph:

The pink colour represents the function $\"\"$ .

The various curve are the sum of the partial functions $\"\"$ .

As the number of terms increases the interval where $\"\"$ is close to the value of $\"\"$ .

Interval of convergence is $\"\"$ .

$\"\"$

Interval of convergence is $\"\"$ .