1.6 參考解答(a) −1≤t≤0-1 \leq t \leq 0−1≤t≤0 {x=t2+2t=(t+1)2−1=y2−1y=t+1\begin{cases} x=t^2+2t=(t+1)^2-1=y^2-1 \\ y=t+1 \end{cases}{x=t2+2t=(t+1)2−1=y2−1y=t+1(b) 1≤t≤21 \leq t \leq 21≤t≤2 7. z(t)=cost+isintz(t)=\cos{t}+i\sin{t}z(t)=cost+isint for 0≤t≤π20 \leq t \leq \frac{\pi}{2}0≤t≤2π