JEE Main & Advanced JEE Main Paper Phase-I (Held on 08-1-2020 Evening)

  • question_answer
    The area (in sq. units) of the region \[\left\{ \left( x,\text{ }y \right)\in {{R}^{2}}:{{x}^{2}}\le y\le 3-2\text{ }x \right\},\]is[JEE MAIN Held on 08-01-2020 Evening]

    A) \[\frac{31}{3}\]             

    B) \[\frac{29}{3}\]

    C) \[\frac{34}{3}\] 

    D) \[\frac{32}{3}\]

    Correct Answer: D

    Solution :

    \[{{x}^{2}}-y\le 0\] and \[2x+y-3\le 0\] For Point of intersection we have \[{{x}^{2}}+2x-3=0~~\] \[\Rightarrow \,\,\,\,\,\,\,\,x=1,x=-3\] \[\therefore \] P (1, 1) and Q (-3, 9) are point of intersection  \[\therefore \] Required area \[\text{=}\int\limits_{-3}^{1}{\left( 3-2x-{{x}^{2}} \right)dx}\] \[\text{=12}-\left( {{x}^{2}} \right)_{-3}^{1}-\frac{1}{3}\left( {{x}^{3}} \right)_{-3}^{1}\] \[\text{=12}-\left( 1-9 \right)-\frac{1}{3}\left( 1+27 \right)\] \[\text{=20}-\frac{28}{3}=11-\frac{1}{3}=\frac{32}{3}\]


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