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Sequence and Series
If a,b,c are real and $\;4a^2+9b^2+16c^2-6ab-12bc-8ac=0\;$ the a,b,c are in
$(a)\;AP\qquad(b)\;GP\qquad(c)\;HP\qquad(d)\;None\;of\;these$
jeemain
math
class11
ch9
sequences-and-series
medium
relationship-between-ap-and-gm
q155
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asked
Jan 22, 2014
by
yamini.v
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Sep 1, 2014
by
sharmaaparna1
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1 Answer
Answer : (c) HP
Explanation : Multiplying by 2 we get ,
$8a^2+18b^2+32c^2-12ab-24bc-16ac=0$
$(2a-3b)^2+(3b-4c)^2+(4c-2a)^2=0$
$2a=3b=4c$
a , b , c are in HP.
answered
Jan 22, 2014
by
yamini.v
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