April Fool's Day.

April 1st

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March 30th.

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wow. Who does that

cute baby

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Showing posts with label sum of infinity. Show all posts
Showing posts with label sum of infinity. Show all posts

Geometric Sequences

A geometric sequence, or geometric progression, is a sequence defined by u1 = a and u i+1 = rui, where r is not equal to 0 or 1.
Examples :

   {2, 4, 8, 16, 32} is a geometric term with six terms.
   {2, 1, 0.5, 0.25, 0.125, 0.0625, . . .} is an infinite geometric sequence.


I will skip the proving parts and jump directly to the formula gained from deriving the equations.

The sum of the geometric series a + ar + ar^2 + ... + ar^n-1, with n terms, is





S∞ is called the sum of infinity of the series.


This following examples are the typical exam-typed question. You should try it out.


Ex. Express the recurring decimal 0.296296296 ... as a fraction.

            The decimal can be written as
                        0.296 + 0.296 x 0.001 + 0.296 x (0.001)^2 + ... and so on
            which is a geometric series with a = 0.296 and r = 0.001. Since | r | < 1, the series iconvergent          with limiting sum 

Since 296 = 8 x 37 and 999 = 27 x 37, this fraction is in its simplest form 8/27.