Sunday 18 December 2011

Reusability or Generalisation of a result in problem solving-3

Let us see another illustration of generalisation of a result

Problem Description : Two circles of radii R and r touch each other externally. Find the radius r1 of circle touching both these externally and their direct common tangent. Also find the radius r2 of circle which touches the second and third circles and their direct common tangent.


Solution


From the above figure, we get the radius r1 as


Similarly, we get r2 as


Now by substituting 

we get


Generalisation : Proceeding like this the radius rn of nth such circle is

1 comment:

  1. thanks to prof.JN Kapoor through his books i cold get to the glimpses of the idea of what generalisation of a result means in maths

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