1.

Consider the polynomial f`(x)= 1+2x+3x^2+4x^3`. Let s be the sum of all distinct real roots of `f(x)`and let `t= |s|`.A. `(-(1)/(4),0)`B. `(-11,-(3)/(4))`C. `(-(3)/(4),(1)/(2))`D. `(0,(1)/(4))`

Answer» Correct Answer - C
Given, `f(x)4x^(3)+3x^(2)+2x+1`
`f(x)=2(6x^(2)+3x+1)`
`impliesD=9-24lt0`
Hence, `f(x)=0` has only one real root.
`f(-(1)/(2))=1-1+3/4-4/8gt0`
`f(-(3)/(4))=1-6/4+27/16-108/64`
`=(64-96+108-108)/(64)lt0`
f(x) changes its sign in `(-(3)/(4),-(1)/(2))`
Hence, f(x)=0 has a root in `(-(3)/(4),-(1)/(2)).`


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