Q11 of 11 Page 5

Find the modulus and the arguments of each of the complex numbers
(i) –3     (ii)         (iii) i


(i) –3     
x + iy = -3
x = -3, y = 0
r =
and tan θ = y/x = 0/3, θ = π .
Thus, the polar coordinates of –1+ i are (3, π ) and its polar form is 3(cos π + i sinπ ).

(ii)      
x + iy =+ i
x = , y = 1
r =
and tan θ = y/x =, θ = π /6.
Thus, the polar coordinates of + i are (2, π /6) and its polar form is 2(cos + i sin).   

(iii) i
x + iy = i
x = 0, y = 1
r =
and tan θ = y/x = ∞ , θ = .
Thus, the polar coordinates of –1+ i are (1, ) and its polar form is (cos+ i sin).

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