Q118 / 160 · AP EAMCET 2018 (25 Apr Shift 1) · Mathematics

The area (in sq. units) of the region lying in the first quadrant and enclosed by the X-axis, the straight line x-3y=0 and the circle x2+y2=4 is

  • Correct answer
    A
    π3
  • B
    2π3
  • C
    π23
  • D
    2π32

Solution

Figure

Required area=Ar∆OAB+∫324-x2dx

Now,

Ar∆OAB=12×3×1=32  ...i

And, let

I=∫324-x2dx

  =12x4-x2+42sin-1x232

=12·2·4-4+2sin-122-32+2sin-132

=2×π2-32+2π3

=π3-32  ...ii

By i & ii, we get

Required area=π3 sq.units.

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

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