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If the line, y=mx, bisects the area of the region

\left \{ \left ( x,y \right ):0\leq x\leq \frac{3}{2},0\leq y\leq 1+4x-x^{2} \right \},then m equals :

  • Option 1)

    \frac{39}{16}

  • Option 2)

    \frac{9}{8}

  • Option 3)

    \frac{13}{3}

  • Option 4)

    \frac{13}{6}

 

Answers (1)

best_answer

 

Geometrical interpretation of a definite integral -

An algebraic sum of the area of the figure bounded by the curve y = f(x), the x axis and the striaght lines x=a and x=b. The areas above x axis are taken as positive and the areas below x axis are taken as negative.  
 

- wherein

Where a< b

Hence

\int_{a}^{b}f\left ( x \right )dx=

ar\left ( PAQP \right )-ar\left ( QTRQ \right )+ar\left ( RBSR \right )

 

 

A_1=\frac{1}{2}*\frac{3}{2}*\frac{3m}{2}= \frac{9m}{8}

Total Area =\int_{0}^{3/2}\left ( -x^2+4x+1 \right )

                    =\left [ \frac{-x^3}{3}+2x^2+x \right ]_{0}^{3/2}

                  =\frac{-9}{8}+\frac{9}{2}+\frac{3}{2}= \frac{39}{8}

So, \frac{39}{8}=2*\frac{9m}{8}

\Rightarrow m= \frac{13}{6}

 


Option 1)

\frac{39}{16}

Option 2)

\frac{9}{8}

Option 3)

\frac{13}{3}

Option 4)

\frac{13}{6}

Posted by

prateek

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