Convert the polar representation of this complex number into its rectangular form:
z = 4(cos pi/2 + i sin pi/2)

Please help Thank you!!!

the picture hasn't showed reload the problem

(0,4)

Step-by-step explanation:

a is the right answer

for this pair of functions g(x)=x-2 and f(x)=|x| is (g o f)(a)= |a| -2

step-by-step explanation:

g(x)=x-2

f(x)=|x|

(g o f)(a)=?

(g o f)(x)=g(f(x))

(g o f)(x)=g(|x|)

(g o f)(x)=|x|-2

(g o f)(a)=|a|-2