Math 141-142 home page
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The applet below lets you explore the graphs of general parabolas with vertex at (h,k). There are two types: the first type is generated by the equation 4a(y-k)=(x-h)2, and the second type by 4a(x-h)=(y-k)2.
The equation 4a(y-k)=(x-h)2 generates a parabola which opens upward if a>0 and opens downward if a<0. The red graph below is the parabola, and the green graph is the directrix of the parabola. Where is the focus? Use the sliders to explore the effect of changing the values of a, h, and k.
MultiGraph applet written by David Eck (http://math.hws.edu/javamath/index.html)
The equation 4a(x-h)=(y-k)2 generates a parabola which opens to the right if a>0 and opens to the left if a<0. The red graph below is the parabola. Where are the focus and the directrix? Use the sliders to explore the effect of changing the values of a, h, and k.
MultiGraph applet written by David Eck (http://math.hws.edu/javamath/index.html)