find the zeros of following quadratic polynomial and verify the relationship between the zeros and the coefficient of the polynomial f(x)=5x-4√3+2√3x²​

Respuesta :

Answer:

[tex]\textsf{Zeros}: \quad x=\dfrac {\sqrt{3}}{2}, \:\:x=-\dfrac {4\sqrt{3}}{3}[/tex]

Step-by-step explanation:

Rewrite the given polynomial in the form ax² + bx + c:

[tex]f(x)=2 \sqrt{3}x^2+5x-4 \sqrt{3}[/tex]

To find the zeros, set the function to zero and solve for x using the quadratic formula.

[tex]\implies 2 \sqrt{3}x^2+5x-4 \sqrt{3}=0[/tex]

Quadratic formula:

[tex]x=\dfrac{-b \pm \sqrt{b^2-4ac} }{2a}\quad\textsf{when }\:ax^2+bx+c=0[/tex]

Therefore,

  • a = 2√3
  • b = 5
  • c = - 4√3

Substituting the values into the quadratic formula:

[tex]\implies x=\dfrac{-5 \pm \sqrt{5^2-4(2\sqrt{3})(-4\sqrt{3})} }{2(2\sqrt{3})}[/tex]

[tex]\implies x=\dfrac {-5 \pm \sqrt {121}}{4\sqrt{3}}[/tex]

[tex]\implies x=\dfrac {-5 \pm 11}{4\sqrt{3}}[/tex]

[tex]\implies x=\dfrac {6}{4\sqrt{3}}, \:\:x=\dfrac {-16}{4\sqrt{3}}[/tex]

[tex]\implies x=\dfrac {3}{2\sqrt{3}}, \:\:x=-\dfrac {4}{\sqrt{3}}[/tex]

[tex]\implies x=\dfrac {\sqrt{3}}{2}, \:\:x=-\dfrac {4\sqrt{3}}{3}[/tex]

The sum of the roots of a polynomial is -b/a:

[tex]\implies -\dfrac{b}{a}=-\dfrac{5}{2 \sqrt{3}}=-\dfrac{5\sqrt{3}}{6}[/tex]

The sum of the found roots is:

[tex]\implies \left(\dfrac {\sqrt{3}}{2}\right)+\left(-\dfrac {4\sqrt{3}}{3}\right)=-\dfrac{5\sqrt{3}}{6}[/tex]

Hence proving the sum of the roots is -b/a

The product of the roots of a polynomial is:  c/a

[tex]\implies \dfrac{c}{a}=\dfrac{-4\sqrt{3}}{2\sqrt{3}}=-2[/tex]

The product of the found roots is:

[tex]\implies \left(\dfrac {\sqrt{3}}{2}\right)\left(-\dfrac {4\sqrt{3}}{3}\right)=-\dfrac{12}{6}=-2[/tex]

Hence proving the product of the roots is c/a

Therefore, the relationship between the roots and the coefficients is verified.