J & K CET Engineering J and K - CET Engineering Solved Paper-2005

  • question_answer
    Let a be the distance between line \[-x+y=2\]  and \[x-y=2\]and \[\beta \] be the distance between the lines \[4x-3y=5\] and \[6y-8x=1,\] then

    A)  \[20\sqrt{2}\beta =11\alpha \] 

    B)  \[20\sqrt{2}\alpha =11\beta \]

    C)  \[11\sqrt{2}\beta =20\alpha \] 

    D)  None of these

    Correct Answer: A

    Solution :

    Given \[\alpha \] be the distance between lines \[x-y+2=0\] and \[x-y-2=0.\] \[\therefore \] \[\alpha =\frac{|2+2|}{\sqrt{1+1}}=\frac{|4|}{\sqrt{2}}=2\sqrt{2}\] and \[\beta \] be the distance between the lines \[4x-3y-5=0\] and \[4x-3y+1/2=0\] \[\therefore \] \[\beta =\frac{\left| 5+\frac{1}{2} \right|}{\sqrt{{{(4)}^{2}}+{{(3)}^{2}}}}=\frac{|11|}{2\sqrt{25}}=\frac{11}{10}\] Now, \[\frac{\alpha }{\beta }=\frac{2\sqrt{2}}{11/10}\] \[\Rightarrow \] \[\frac{\alpha }{\beta }=\frac{20\sqrt{2}}{11}\] \[\Rightarrow \] \[20\sqrt{2}\,\,\beta =11\alpha \]


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