Get Answers to all your Questions

header-bg qa

 A point  P  moves so that the sum of squares of its distances from the points \mathrm{(1,2)} and \mathrm{(-2,1)} is \mathrm{14}. Let \mathrm{f(x, y)=0} be the locus of \mathrm{p,} which intersects the x-axis at the points \mathrm{A,B} and the y-axis at the points \mathrm{C,D}.  Then the area of the quadrilateral  \mathrm{\mathrm{ACBD}}  is equal to: 

Option: 1

\frac{9}{2}


Option: 2

\frac{3 \sqrt{17}}{2}


Option: 3

\frac{3 \sqrt{17}}{4}


Option: 4

9


Answers (1)

best_answer

\mathrm{\Rightarrow (x-1)^{2}+(y-2)^{2}+(x+2)^{2}+(y-1)^{2}=14} \\

\mathrm{\Rightarrow x^{2}+y^{2}+x-3 y-2=0} \\

\mathrm{ \text { Put } x=0 }\\

\mathrm{\Rightarrow y^{2}-3 y-2=0} \\

\mathrm{\Rightarrow y=\frac{3 \pm \sqrt{17}}{2}} \\

\mathrm{\Rightarrow x^{2}+x-2=0 \Rightarrow(x+2)(x-1)=0 }\\

\mathrm{\therefore A(-2,0), B(1,0), C\left(0, \frac{3+\sqrt{17}}{2}\right), D\left(0, \frac{3-\sqrt{17}}{2}\right)} \\

\mathrm{\text { Area }=\frac{1}{2} \times 3 \times \sqrt{17}=\frac{3 \sqrt{17}}{2} }

Hence correct option is 2

 

Posted by

SANGALDEEP SINGH

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE