Q.41. a > b > 0 and 2 x 2 - a x - b 2 = 0 then
(A) both roots lie between - a 2 and a
(B)  both roots are positive
(C) both roots are negative
(D) both roots are imaginary

Let fx=2x2-ax-b2=0Since coefficent of x>0, therefore, it is an upward parabola.Vertex of parabola a'x2+b'x+c' i given by x=-b'2a'Discriminant D=b'2-4a'c'=a2+8b2>0It has real and distinct rootsHereVertex=--a4=a4f-a2=2-a22+a22-b2=2a24+a22-b2=a22+a22-b2=a2-b2Since a>b>0a2>b2a2-b2>0f-a2>0fa=2a2-a2-b2=a2-b2fa>0Hence this means that the roots lie between -a2, and a. 

 

  • 1
Us the ans in A or c
  • -1
Is the answer is A Or C
  • 1
Its A but how??
  • -1
What are you looking for?