How to write a circuit value whit complex numbers

Can someone help me?

I need to write this in matlab:

I= 220 cos(50t+30)/52.4 = 4.2 cos(50t+30)

Bit i have no idea also 220cos its complex number of a circuit

Answer 1

[Voss]

I = 220*cos(50*t+30)/52.4;