CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2002

  • question_answer
    The equation of the smallest degree with real coefficients having\[1+i\]as one of the roots, is:

    A)  \[{{x}^{2}}+x+1=0\]      

    B)                         \[{{x}^{2}}-2x+2=0\]

    C)                         \[{{x}^{2}}+2x+2=0\]    

    D)                         \[{{x}^{2}}+2x-2=0\]

    E)                         none of these

    Correct Answer: B

    Solution :

    If\[1+i\]is one root of equation, then another root will be\[1-i\]. \[\therefore \] Sum of roots\[=1+i+1-i=2\] and product of roots\[=(1+i)(1-i)=1-{{i}^{2}}\]         \[=1+1=2\] \[\therefore \]Required equation will be \[{{x}^{2}}-\] (sum of roots) x + (product of roots) = 0 \[\Rightarrow \]        \[{{x}^{2}}-2x+2=0\]


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