Q.

A line passing through the point A(–2, 0), touches the parabola P : y2=x2 at the point B in the first quadrant. The area, of the region bounded by the line AB, parabola P and the x-axis, is :          [2025]

1 73  
2 2  
3 3  
4 83  

Ans.

(4)

Given parabola P : y2=x2 and line is passing through A(–2, 0)

Tangent is y = m(x + 2)

 (m(x+2))2=x2

 m2x2+(4m21)x+(4m2+2)=0

As D = 0

 (4m21)2=4m2(4m2+2)  m=14

So, tangent is y=14(x+2)

Point of tangency is (6, 2)

   Area of region =02(y2+2)(4y2)dy

                                        =838+8=83 sq. units.