Respuesta :

mreijepatmat
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