CAT4MBA

1)If k and 2k^2 are the roots of x^2-px+q=0, then the value of q+4q^2+6pq is...

ans: q^2
       p^3
       0 
       2p^3

Soln. For u im tryin in detail....Check it out...

       Formula: if  ax^2+bx+c=0 has two roots x nd y, dn x+y=-b/a,nd xy=c/a

       k+2k^2=-(-p)/1=p...(i), 
       2k^2 x k=q =>q=2k^3.....(ii)[Frm above formula, here x=k,nd y=2k^2]
        
       q+4q^2+6pq=2k^3+4(2k^3)^2+6(k+2k^2)x2k^3=2k^ 3+16k^6+12k^4+24k^5

                        =2(k^3+8K^6+6k^4+12k^5)
                        =2[k^3+(2k^3)³+3 x k^2 x 2k^2 +3 x k x (2k^2)² ]
                        =2(k+2k^2)³[Formula of (a+b)³ Where a=k nd b=2k^2] 
                        =2p^3[From (i)]

So option (d) is correct..... 

Giv ur best to d world.
Nd d best will cm back to u.....

Regards,
Dipanjan......

U know wt friend, I have started liking maths problems, Just becoz am now assured that if I got stuck somewhere, or want to clear the basics , I can come back to u all friends like a child who is curious to learn everything around.

I wish I had got this type of  learning exp in my early education.

Thanks a lot again friend.

My frn go ahead....We r wd u...

Happy solvin,

Regards,
Dipanjan......