Answer:
We just need to evaluate and get f(2i)=0, f(-2i)=0.
Step-by-step explanation:
Since 
, then 
, and we can apply this when we evaluate 
for 2i and -2i.
First we have:
Which shows that 2i is a zero of f(x).
Then we have:
Which shows that -2i is a zero of f(x).
Since the side which measures 10 is a vertical projection of the hipotenuse x on a 20 degree angle:
10 = x*sin(20°)
x = 29.238044
Since we have to round to the nearest hundreth:
x = 29.24 m
