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Algebra

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Joined:	29 Jun 2008
Post:	4

29 Jun 2008 18:53:51 IST

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solve kar ke dekha

None

if both the roots of quadratic equation are less than 5

x^2-2kx+k^2+k-5

then k lies in the interval

a- ( -,4)

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Priyesh

Blazing goIITian

Joined: 18 Feb 2007

Posts: 1042

29 Jun 2008 19:05:33 IST

Like 2 people liked this

f(x) = x^2- 2kx + k^2 + k - 5

since roots r real

=> 20 - 4k >= 0

=>k<= 5 ------------------------------------------------1

also f(5)>0

=> k^2 - 9k + 20 > 0

=> k<4 & k> 5 --------------------------------------2

from 1 & 2

k < 4

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