Question
Question: If the roots of the equations \(5 + 4x - 4x^{2}\) and \(x\) be real, then....
If the roots of the equations 5+4x−4x2
and x be real, then.
A
(x−c)(x−a)(x−b)
B
a>b>c
C
a<b<c
D
a>c<b
Answer
a>b>c
Explanation
Solution
Equations 31 and
32 have real roots, then from first 34⇒ x2+x+1+2k(x2−x−1)=0 .....(i)
and from second sinA,sinB,cosA (for real root )
⇒ x2+2xcotB+1=0 .....(ii)
From (i) and (ii), we get result x4−4x3+ax2+bx+1=0.