How do you find the sum of the infinite geometric series 72 + 12 + 2 + +… ?
The formula for the sum of an infinite series is
where r is the common ratio and a is the first term.
First, you must find the common ratio, r, of the series.
The sum is
Below I have posted one problem for your practice.
- Find the wanted information.
a) An infinite geometric series has a third term of 18 and a common ratio of
b) A pendulum has a first swing of 186 centimeters and a second swing of 124 centimetres. Assuming the pendulum swings forever, find the total distance travelled, rounded to the closest hundredth when necessary.