Algebra

Pranav's Avatar
Hot goIITian

Joined: 5 Feb 2012
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5 Apr 2012 14:42:11 IST
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find "d"
Engineering Entrance , JEE Main , JEE Main & Advanced , Mathematics , Algebra

Solve :(1-9d^2 ) (1-d^2)=385



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Blazing goIITian

Joined: 21 Mar 2012
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5 Apr 2012 15:01:59 IST
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d=8/3
hemang's Avatar

Blazing goIITian

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6 Apr 2012 13:42:23 IST
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actually d = + 8/3, -8/3, +i*sqrt(6), -i*sqrt(6). where i = iota.

 

ronnie's Avatar

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6 Apr 2012 14:06:47 IST
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i agree wd hemang as i too felt the need of some restrictions...i thnk u got it 4m wolfram alpha...basically we resolve into factors the LHS and RHS...but we get 4 factors of LHS and 3 p. factors of rhs...so 'd' had to be a fraction and solving i got +/-8/3

Blazing goIITian

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6 Apr 2012 14:34:39 IST
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i got d=+-8/3 only
hemang's Avatar

Blazing goIITian

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9 Apr 2012 11:47:15 IST
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ha ha.

no need for wolfram alpha.

(1-9m)(1-m) = 385.

where d^2 = m.

from here we get, d^2 = 64/9 and -6.

so we get d = +8/3, -8/3, +iota*sqrt{6} and -iota*sqrt{6}.

wolfram alpha is the last resort...

 

 




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