Find the modulus of each of the following complex numbers and hence express each of them in polar form:
= -i
Let Z = -i = r(cosθ + isinθ)
Now, separating real and complex part , we get
0 = rcosθ……….eq.1
-1 = rsinθ …………eq.2
Squaring and adding eq.1 and eq.2, we get
1 = r2
Since r is always a positive no., therefore,
r = 1,
hence its modulus is 1.
now, dividing eq.2 by eq.1 , we get,
Tanθ = -∞
Since cosθ = 0, sinθ = -1 and tanθ = -∞, therefore the θ lies in fourth quadrant.
Tanθ = -∞, therefore
Representing the complex no. in its polar form will be
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