Q49 / 75 · JEE Main 2020 (04 Sep Shift 2) · Mathematics

The area (in sq. units) of the largest rectangle ABCD whose vertices A and B lie on the x-axis and vertices C and D lie on the parabola, y=x2-1 below the x-axis, is :

  • A
    233
  • B
    133
  • C
    43
  • Correct answer
    D
    433

Solution

Figure

A(α,0),β(-α,0)

⇒Dα,α2-1

Area (ABCD) = (AB) (AD)

⇒S=(2α)1-α2=2α-2α3

dsdα=2-6α2=0⇒α2=13⇒α=13

 Area =2α-2α3=23-233=433

 

Hence, the correct answer is option: 'D'.

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