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If \alpha ,\beta ,\gamma are roots of x^{3}-x+2= 0 then the equation whose roots are \alpha +\beta +2\gamma ,\beta +\gamma +2\alpha  &  \gamma +\alpha +2\beta  will be

  • Option 1)

    x^{3}+x-2= 0

  • Option 2)

    x^{3}+x+2= 0

  • Option 3)

    x^{3}-x+2= 0

  • Option 4)

    x^{3}-x-2= 0

 

Answers (1)

best_answer

Let y=\alpha +\beta +2\gamma =\alpha +\beta +\gamma +\gamma =0+\gamma

\Rightarrow \: \gamma =y

now, \gamma will satisfy the given equation so y^{3}-y+2=0

\therefore equation is x^{3}-x+2=0

\therefore  Option (C)

 

Transformation of equation -

To find equation whose roots are symmetrical functions of \alpha and \beta , Where \alpha & \beta are roots of some other equation. 

- wherein

Take any of the root to be equal to y  &  calculate \alpha  or  \beta  accordingly in terms of y  & satisfy the given equation to get required equation.

 

 


Option 1)

x^{3}+x-2= 0

This is incorrect

Option 2)

x^{3}+x+2= 0

This is incorrect

Option 3)

x^{3}-x+2= 0

This is correct

Option 4)

x^{3}-x-2= 0

This is incorrect

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divya.saini

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