harmonic mean

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harmonic mean

by rupsk » Thu Aug 18, 2011 6:45 am
The harmonic mean of the roots the equation is
(5+sqrt 2)x*x - (4 + sqrt 5)x + (8+2 * sqrt 5)=0

A. 6
B. 8
C. 2
D. 4
E. 5

sol: hm= 2* product of root/ sum of root
product of root = (8+2 * sqrt 5)/(5+sqrt 2)
sum of root =(4 + sqrt 5) /(5+sqrt 2)
hm = 2*2 =4
but my answer is incorrect, please correct me where i did wrong.
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by Anurag@Gurome » Thu Aug 18, 2011 7:17 am
rupsk wrote:sol: hm= 2* product of root/ sum of root
product of root = (8+2 * sqrt 5)/(5+sqrt 2)
sum of root =(4 + sqrt 5) /(5+sqrt 2)
hm = 2*2 =4
but my answer is incorrect, please correct me where i did wrong.
Your method and answer both are correct. Please check the authenticity of the material you are using.
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