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Application Of Integrals

Question
CBSEENMA12036291

Let g(x) = cos x2, f(x) = x and α, β (α <β) be the roots of the quadrtic equation 18x2 - 9πx + π2 = 0. Then the area (in sq. units) bounded by the curve y = (gof)(x) and the lines x = α, x = β and y = 0 is

  • 12(2-1)

  • 12(3-1)

  • 12(3+1)

  • 12(3-2)

Solution

B.

12(3-1)

18x2-9πx + π2 = 0

(6x -π)(3x-π) = 0

 x = π6,π3α = π6, β = π3y = (gof)(x) =cosxArea = π6π3 cos x dx = (sin x )π6π3 = 32 -12 = 12(3-1) sq.units