매개곡선
정의:
$\displaystyle x=f(t),y=g(t)$ ← 매개방정식
$\displaystyle t$ ← 매개변수
예:
$\displaystyle x=t^2,y=t$
$\displaystyle \Rightarrow x=y^2$
(포물선)
예:
$\displaystyle x=2\cos t,y=2\sin t(0\le t\le 2\pi)$
$\displaystyle \Rightarrow x^2+y^2=4$
예:
$\displaystyle x=\cos t,y=\cos^2 t$
$\displaystyle \Rightarrow y=x^2(-1\le x\le1,0\le y\le 1)$
예:
$\displaystyle x=3\cos t,$
$\displaystyle y=2\sin t (0\le t \le 2\pi)$
$\displaystyle \Rightarrow\left(\frac{x}3\right)^2+\left(\frac{y}{2}\right)^2=\cos^2t+\sin^2t=1$
$\displaystyle \frac{x^2}{9}+\frac{x^2}{4}=1$ (타원)
사이클로이드,cycloid curr
사이클로이드,cycloid (굴렁쇠선)
$\displaystyle x=r(\theta-\sin\theta)$
$\displaystyle y=r(1-\cos\theta)$