Respuesta :

bunnyo

Step-by-step explanation:

cos^2(t)+sin^2(t)=1

4cos^2(t)/4 + 81sin^2(t)/81 =1

2^2(cos^2(t))/2^2 + 9^2(sin^2(t))/9^2=1

[2cos(t)]^2/2^2 +[ 9sin(t)]^2/9^2=1

since x^2/2^2 +y^2/9^2=1

X=2cos(t) ,y=9sin(t)

X(t)= 2cos(t) here r=2

y(t)=9sin(t)