Functions

For all complex numbers z,

let f(z) = z^2 if z is not real, f(z) = 2z if z is real.

 

Find f(f(f(f(1+i))))

 

\(f(i+1)=(1+i)^2=2i\\ f(2i)=(2i)^2=-4\\ f(-4)=2*-4=-8\\ f(-8)=2*-8=-16\)