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The function kf(x)=a x^2+b x^2+c x+d has...

The function k`f(x)=a x^2+b x^2+c x+d` has three positive roots. If the sum of the roots of `f(x)` is 4, the larget possible inegal values of `c//a` is ____________.

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The correct Answer is:
5

Let `ax^(2)+bx^(2)+cx+d=0` has roots p,q,r
`pq+qr+rp=(c)/(a)" "(1)`
but `pq+qr+rplep^(2)+q^(2)+r^(2)`
`=(p+q+r)^(2)-2sumpq`
`therefore3(pq+qr+rp)le(p+q+r)^(2)=16`
`therefore3(c)/(a)le16`
`rArr(c)/(a)le(16)/(3)`
`rArr` largest integral value of `(c)/(a)` is 5
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