The <em><u>correct answer</u></em> is:
Explanation:
To write a composite function, we apply one function to another given function. In this case, we want to find area in terms of time; this means that the function A(r) gets applied to the function r(t).
In order to do this, we replace r with r(t). We already know that r(t)=0.5+2t; this means we replace r with 0.5+2t:
A(r(t))=π(0.5+2t)²
To simplify this, we simplify the squared term:
A(r(t)) = π(0.5+2t)(0.5+2t)
A(r(t)) = π(0.5*0.5+0.5*2t+2t*0.5+2t*2t)
A(r(t)) = π(0.25+t+t+4t²)
A(r(t)) = π(0.25+2t+4t²)