If z is a complex number of unit modulus and argument θ, then arg is equal to
-θ
π/2-θ
θ
θ
The equation esinx-e-sinx -4 = 0 has
infinite number of real roots
No real root
exactly one real root
exactly one real root
Let α, β be real and z be a complex number. If z2 + αz + β = 0 has two distinct roots on the line Re z = 1, then it is necessary that
β ∈(0, 1)
β ∈(-1, 0)
|β| = 1
|β| = 1
If ω(≠1) is a cube root of unity, and (1 + ω)7 = A + Bω.Then (A, B) equals
(0,1)
(1,1)
(1,0)
(1,0)
If, for a positive integer n, the quadratic equation,
x(x + 1) + (x + 1) (x + 2) + .....
+ (x + n -1 ) (x + n) = 10n
has two consecutive integral solutions, then n is equal to :
11
12
9
9
If the roots of the equation bx2+ cx + a = 0 be imaginary, then for all real values of x, the expression 3b2x2 + 6bcx + 2c2 is
greater than 4ab
less than 4ab
greater than -4ab
greater than -4ab
C.
greater than -4ab
As, bx2 + cx + a = 0 has imaginary roots
So, c2< 4ab
Now, 3b2x2 + 6bcx + 2c2
= 3(bx + c)2– c2≥ – c2≥ – 4ab
The quadratic equations x2 – 6x + a = 0 and x2 – cx + 6 = 0 have one root in common. The other roots of the first and second equations are integers in the ratio 4 : 3. Then the common root is
1
4
3
3