Express the following complex number in polar form and exponential form. -i
Let z = -i = 0 – i
a = 0, b = -1
z lies on negative imaginary Y-axis.
|z| = r = \(\sqrt{a^2+b^2}=\sqrt{0^2+(-1)^2}=1\) and
θ = amp z = 270° = \(\frac{3\pi}2\)
The polar form of z = r (cos θ + i sin θ)
= 1 (cos 270° + i sin 270°)
= 1\((cos\frac{3\pi}2+i sin\frac{3\pi}2)\)
The exponential form of z = reiθ = e\(\frac{3\pi}2i\)