RAJASTHAN ­ PET Rajasthan PET Solved Paper-2011

  • question_answer
    If the roots of the equation\[{{x}^{2}}+px+q=0\]differ by 1, then

    A)  \[{{p}^{2}}=4q\]

    B)  \[{{p}^{2}}=4q+1\]

    C)  \[{{p}^{2}}=4q-1\]

    D)  \[{{p}^{2}}=q\]

    Correct Answer: B

    Solution :

     Let \[\alpha ,\alpha +1\]be the roots of the given equation, then \[\alpha +\alpha +1=-p\] \[2\alpha =-p-1\] \[\Rightarrow \] \[\alpha =-\frac{p+1}{2}\] Also,   \[a(a+1)=q\] \[\Rightarrow \] \[-1+{{p}^{2}}=4q\] \[\Rightarrow \] \[{{p}^{2}}=4q+1\]


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