2. Questions Bank
  3. JEE Main & Advanced
  4. Mathematics
  5. Complex Numbers and Quadratic Equations

JEE Main & Advanced Mathematics Complex Numbers and Quadratic Equations Question Bank Relation between roots and coefficients

  • question_answer
    If \[\alpha \] and \[\beta \] are the roots of the equation \[4{{x}^{2}}+3x+7=0\], then \[\frac{1}{\alpha }+\frac{1}{\beta }\]= [MNR 1981; RPET 1990]

    A) \[-\frac{3}{7}\]

    B) \[\frac{3}{7}\]

    C) \[-\frac{3}{5}\]

    D) \[\frac{3}{5}\]

    Correct Answer: A

    Solution :

    Given equation \[4{{x}^{2}}+3x+7=0\], therefore \[\alpha +\beta =-\frac{3}{4}\]  and \[\alpha \beta =\frac{7}{4}\] Now\[\frac{1}{\alpha }+\frac{1}{\beta }=\frac{\alpha +\beta }{\alpha \beta }=\frac{-3/4}{7/4}=\frac{-3}{4}\times \frac{4}{7}=-\frac{3}{7}\].


You need to login to perform this action.
You will be redirected in 3 sec spinner