Answer:
E(t) = [ 4cos(t) , 2 sin(t) ]
Step-by-step explanation:
The elipse ecuacion is of the form:
 (x² ÷ a² ) + (y² ÷ b² ) = 1   Where a and b are the horizontal and vertical semi-diameters respectively
In our particular case   x²/16 + y²/ 4 = 1
That form suggests  (x/a)² + (y/b)² =1      Â
And again in our case   x²/16  + y²/4 = 1                            the same shape of         sin²α +cos²α = 1
So we call x = 4 cos(t ) Â and the
We need to find y    Â
x²/16  + y²/4 = 1 Â
x²/16  + y²/4 = 1  ⇒   (x²  +  4y²) ÷ 16  = 1
Solving for y   (x²  +  4y²)  = 16    ⇒  y²  = ( 16 - x²) ÷4
as  x = 4 cos(t)  ⇒  y²  =  (16 - 16cos²(t)) ÷ 4   y = √4 (1 -cos²(t)
y = 2 sin (t)
So the vector parametrization of the elipse is
E(t) = [ 4cos(t) , 2 sin(t) ]