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sahilwasan said – Tue, 10 Mar 2009 19:07:08 -0000 ( Edit Link )

If the quadratic equation (a^2+b2)x^{2+2b(a+c)x+(b}2+c^2)=0 has equal roots, then (A) a, b and c are in A.P. (B) a, b and c are in G.P. (C) a, c and b are in A.P. (D) a, c and b are in G.P.

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spiyr said – Sun, 19 Apr 2009 20:26:08 -0000 ( Flag Edit Mark / Unmark Best Link )

option A
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1. raj beniwal said – Thu, 13 Aug 2009 15:35:02 -0000 ( Flag Edit Link )
  
  i think option must be C
  
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deepa mittal said – Wed, 23 Sep 2009 18:35:09 -0000 ( Flag Edit Mark / Unmark Best Link )

For equal roots, D = 0

applyin the condition we get:

4b ^2(a+c) ^2 = 4 (a ^2 + b ^2)(b ^2 + c ^2)

on solvin above we get:

(b ^2 – ac) ^2 = 0

hence b2 = ac

hence a, b & c are in GP and answer is B
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