The value of is equal to
(A) 4
(B) 6
(C) 8
(D) 2
Answer:(D)
Explanation:
We have
[by De-Moivre’s theorem]
The solution of the equation is
(A)
(B)
(C)
(D)
Answer:(A)
Explanation:
Let
Comparing real and imaginary parts
we have and
Now substitute the value of in
we get
If is purely imaginary, then
(A)
(B)
(C)
(D) None of these
Answer:(C)
Explanation:
Let , where
As we know by componendo and dividendo that
So we have