58-08 Basics of Arithmetic & Geometric Progression

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Example:

A) If s₄  =  156 and s₈  =  97656, find a and r.

Solution:

  1) Let " a " be the 1st tern and " r " be the common ratio. So we have,

6) Answer: We have a = 1 when r = 5 and a = -3/2 when r = - 5

Note: Here the division of 97656 by 156 is complicated as we should not use the calculator. Please see the following simple method of calculation so that you will save a lot of time and you can't make any calculation mistakes. In the following method, you may observe that there are a few more steps to be done but all these steps are simple to understand the calculation. You may also notice that this calculation process is really very simple. So we will solve the same problem with another Simple Method.

Solution:

 1) Let " a " be the 1st tern and " r " be the common ratio. So we have,

 
 

6) Answer: We have a = 1 when r = 5 and a = -3/2 when r = - 5

Some more Problems with the Simple Method of calculations will be published in the Next Blog.

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Anil Satpute