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Share/Save/Bookmark Login/ Register to Bookmark Topic : "Quad... answer only..." Started by Abhishek Priyam

Abhishek Priyam

#1 Posted 0:50pm 11-02-09  

Quad... answer only...

Don't want soln or any hint just the answer..

If the roots of the equation ax[p]2[/p]+cx+c=0 be in ratio p:q then....

[sqrt]p/q[/sqrt]+[sqrt]q/p[/sqrt]+[sqrt]c/a[/sqrt]=?



http://priyamsays.blogspot.com    

Двҥїяuρ

#2 Posted 0:58pm 11-02-09  

Re: Quad... answer only...

2√2[i][b]i  [/b][/i]???
http://abhirupsarkar.webs.com/  Edited on 0:09pm 12-02-09    

Abhishek Priyam

#3 Posted 0:59pm 11-02-09  

Re: Quad... answer only...

lol...
http://priyamsays.blogspot.com    

Abhishek Priyam

#4 Posted 1:01pm 11-02-09  

Re: Quad... answer only...

this is from B.U. 77,64 R.U. 69,75 and they asked to prove it is equal to [b]zero[/b].. :D

thats why i posted this question...

[4]

In hall and Knight too. same question... and in few books they proved it to be zero by two methods.. lol
http://priyamsays.blogspot.com    

tapanmast

#5 Posted 1:06pm 11-02-09  

Re: Quad... answer only...

howz dat possible????????????????

dat means all p/q , q/p , c/a hav 2 be individually zero as their sq roots cant b -ve.....

which is impossible as if p/q =0, means p=0; then how can q/p=0 it shud b ∞....


I M SHOCKD by the answer
   

Двҥїяuρ

#6 Posted 1:06pm 11-02-09  

Re: Quad... answer only...

take a eqn like dis

2x[p]2[/p]-x-1=0

then...[5]

may b a stupid post[11]
http://abhirupsarkar.webs.com/    

Двҥїяuρ

#7 Posted 1:10pm 11-02-09  

Re: Quad... answer only...

Priyam ..post the soln plzzzz....
http://abhirupsarkar.webs.com/    

Abhishek Priyam

#8 Posted 1:11pm 11-02-09  

Re: Quad... answer only...

i am also shocked... by the answer.. and they have asked it for 4 years.... :P

@abhirup... nice!!  try that way...

http://priyamsays.blogspot.com    

Abhishek Priyam

#9 Posted 1:15pm 11-02-09  

Re: Quad... answer only...

yeah tapan i also thought the same...

each must be zero...

so p=q=c=0

then eqn is ax[p]2[/p]=0

and about soln given in book dekhte hain.. kya kiya hai...



http://priyamsays.blogspot.com    

theprophet

#10 Posted 1:45pm 11-02-09  

Re: Quad... answer only...

are you sure you have written down the question properly?
   

Anurag

#11 Posted 1:54pm 11-02-09  

Soln

Let the roots be kp and kq (k is an arbitrary constant);
Then,
√(p/q)+√(q/p)+√(c/a)=
(p+q)/√(pq) + √(c/a)=
(kp+kq)/√(kp.kq) + √(c/a)=
Sum of rts/√(Prod of rts) + √(c/a)=
(-c/a)/√(c/a) + √(c/a)=
-√(c/a) + √(c/a) = 0!!
 Edited on 2:30pm 11-02-09    

johny

#12 Posted 1:55pm 11-02-09  

Re: Quad... answer only...

priyam  verify hall and knight once more
   

Anurag

#13 Posted 1:56pm 11-02-09  

Cont.

U gus hav ignored the fact that the roots can be imaginary, in which case, the root of the ratio of the roots can be -ve.
   

Nishant

#14 Posted 2:16pm 11-02-09  

Re: Quad... answer only...

if you see correctly, then the given sum will be

√(p/q)+√(q/p)+√(c/a)=
(|p|+|q|)/√(pq)| + √(c/a)=
(k|p+k|q|)/√(kp.kq) + √(c/a)


whcih will not be the thing given unless we know that the roots are not real!



Does this make more sense?!? (I am not very sure bcos i dont want to take risk of trying to defy a classic like Hall and Knight.)

Opinions invited :)

Great that you noticed this abhishek
-when spring comes, it melts the snow one flake at a time…    

Celestine

#15 Posted 4:56pm 11-02-09  

Re: Quad... answer only...

its not 0

the fact is p/q is ω or ω[p]2[/p]   and  proceed

(  the fallacy is wen u take √a√a = a wen  its actually -a )
   

Двҥїяuρ

#16 Posted 0:13pm 12-02-09  

Re: Quad... answer only...

When the roots are real then it is not 0.

like...for the eqn 2x[p]2[/p]-x-1=0 ...you can check this.
http://abhirupsarkar.webs.com/    

Двҥїяuρ

#17 Posted 0:58pm 14-02-09  

Re: Quad... answer only...

α+β=-c/a
αβ=c/a


α+β=-αβ

=>α+β=[b]-[sqrt]αβ[/sqrt]*[sqrt]αβ[/sqrt][/b]

=>[sqrt]α/β[/sqrt]+[sqrt]β/α[/sqrt]=-[sqrt]αβ[/sqrt]

=> √p/q+√q/p+√c/a=0!!!

problem is there in 2nd line when we consider -αβ= -[sqrt]αβ[/sqrt]*[sqrt]αβ[/sqrt]
as here we r only considering both+ve square roots of αβ



http://abhirupsarkar.webs.com/  Edited on 0:59pm 14-02-09    
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