FIND THE VALUE OF AN INFINITE GEOMETRIC SERIES

Finding the value of an infinite geometric series is to find the sum of the terms in the series.

Formula to find the sum of infinite geometric series :

where -1 < r < 1

In the formula above, a1 is the first term of the series and is the common ratio.

r = second term/first term

or

r =a2/a1

Note :

In an infinite geometric series, if the value of r is not in the interval -1 < r < 1, then the sum does not exist.

Find the values of the following infinite geometric series :

Example 1 :

1 + 3/4 + 9/16 + 27/64 ............

Solution :

In the given geometric series,

a1 = 1

r = a2/a1

= (3/4)/1

= 3/4

Formula to find the sum of an infinite geometric series :

S = a1/(1 - r)

Substitute a1 = 1 and r = 3/4.

S= 1/(1 - 3/4)

= 1/(1/4)

= 1(4/1)

= 4

The value of the given infinite geometric series is 4.

Example 2 :

1 + 2/3 + 4/9 + 8/27 ............

Solution :

In the given geometric series,

a1= 1

r = a2/a1

= (2/3)/1

= 2/3

Formula to find the sum of an infinite geometric series :

S= a1/(1 - r)

Substitute a1= 1 and r = 2/3.

S= 1/(1 - 2/3)

= 1/(1/3)

= 1(3/1)

= 3

The value of the given infinite geometric series is 3.

Example 3 :

1 + 1/2 + 1/4 + 1/8 ............

Solution :

In the given geometric series,

a1= 1

r = a2/a1

= (1/2)/1

= 1/2

Formula to find the sum of an infinite geometric series :

S= a1/(1 - r)

Substitute a1= 1 and r = 1/2.

S= 1/(1 - 1/2)

= 1/(1/2)

= 1(2/1)

= 2

The value of the given infinite geometric series is 2.

Example 4 :

1 + 3/5 + 9/25 + 27/125 ............

Solution :

In the given geometric series,

a1= 1

r = a2/a1

= (3/5)/1

= 3/5

Formula to find the sum of an infinite geometric series :

S= a1/(1 - r)

Substitute a1= 1 and r = 3/5.

S= 1/(1 - 3/5)

= 1/(2/5)

= 1(5/2)

The value of the given infinite geometric series is 5/2.

Example 5 :

1 + 1/4 + 1/16 + 1/64 ............

Solution :

In the given geometric series,

a1= 1

r = a2/a1

= (1/4)/1

= 1/4

Formula to find the sum of an infinite geometric series :

S= a1/(1 - r)

Substitute a1= 1 and r = 1/4.

S= 1/(1 - 1/4)

= 1/(3/4)

= 1(4/3)

The value of the given infinite geometric series is 4/3.

Kindly mail your feedback to v4formath@gmail.com

We always appreciate your feedback.

©All rights reserved. onlinemath4all.com

Recent Articles

  1. SAT Math Resources (Videos, Concepts, Worksheets and More)

    Nov 19, 24 09:14 AM

    SAT Math Resources (Videos, Concepts, Worksheets and More)

    Read More

  2. Digital SAT Math Problems and Solutions (Part - 73)

    Nov 19, 24 09:13 AM

    digitalsatmath58.png
    Digital SAT Math Problems and Solutions (Part - 73)

    Read More

  3. Digital SAT Math Problems and Solutions (Part - 72)

    Nov 18, 24 08:15 AM

    digitalsatmath57.png
    Digital SAT Math Problems and Solutions (Part - 72)

    Read More