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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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