Write the complex number in polar form. Express the argument in degrees. 4i

Write 4i in the following form r (cos Ф + I sin Ф)

Since it's 4i, that means 4 is on the y-axis, So r = 4 and Ф = 90°

Hence the equation is 4 (cos 90° + i sin 90°)

Proof: cos 90° = 0 and sin 90° = 1

4[0 + i (1) ] = 4i