Chapter 8 - Section 8.4 - Plane Curves and Parametric Equations - 8.4 Exercises - Page 617: 15

(a) See the graph. (b) $y=x^2$

(a) $x=sin^2t$ and $y=sin^4t$ are periodic functions. The maximum value of $sin^2t$ and $sin^4t$ is $1$ and the minimum is $0$. In these points the functions change the directions. That is, $x$ and $y$ move back and forth from $(0,0)$ to $(1,1)$. (b) $x=sin^2t$ $x^2=sin^4t$ $y=sin^4t$ $y=x^2$