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deep01 (42)

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The equation


          (x-a)3+(x-b)3+(x-c)3=0  ,  has


 


(A) all the roots real


(B) one real and two imaginary roots


(C) three real roots namely x=a,x=b,x=c


(D) none 

    
deedee (1944)

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is d answer A................... ??


don't walk as if u rule d world
walk as if u dont care who rules d world

-this is knw as attitude


B who u r and say wat u feel ......
coz those who mind don't matter ........
and those who matter dont mind ......... :)


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deep01 (42)

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no it's (b)

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deep01 (42)

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 someone pls answer........................

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whaler_4 (24)

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Damn this is a crazy Q

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feynmann (2236)

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It must have some conditions on a,b,c as if a=b=c then it has three real roots !!

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feynmann (2236)

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Assuming that a!=b!=c I can prove that the eqn can't have 3 real roots and hence a,b, c being real and complex roots occuring in conjugate pairs the option (b) is correct .


The proof goes as follows :


Denote the LHS by f(x) and assume that it has three real roots . Then f'(x) =0must have atleast two real roots


That is (x-a)^2 + (x-b)^2 + (x-c)^2 = 0 has atleast two real roots


but it is give that a!=b!=c , so the above eqn has no real roots at all !!


Hence it must have one real and two conjugate imaginary roots .


 

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hsbhatt (4912)

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Yeah, pls check if there is any condition on a,b and c


Time wounds all heels
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