Let α and β α < β are roots of 18 x 2 - 9 π x + π 2 = 0 ,   f x = x 2…

Let α and βα<β are roots of 18x2-9πx+π2=0, fx=x2, gx=cosx. Then αβxgofxdx=
  1. 3-14
  2. 34
  3. 2+32
  4. 12sinπ29-sinπ236

Solution

Given fx=x2, gx=cosx

i.e. gfx=cosx2

For 18x2-9πx+π2=0

roots are 9π±81π2-72π236=9π±3π36=π3, π6

i.e. α=π6, β=π3

So, αβxgfxdx=π6π3xcosx2dx

Let x2=t; xdx=dt2

12π236π29costdt=12sinπ29-sinπ236

Asked in: AP EAMCET 2022 (04 Jul Shift 1)

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