**Parabola Plotting Web Pages**

**Thanks to HTML5, graphics is now available on web
pages.**

**Using this feature to design parabolas, is as an**

**example of what is now available. **

**Different applications require parabolas having
different**

**focal points. For convenience, let focal length be
define**

**relative to the parabola's radius. The old camera flash **

**bulbs use to use a parabola similar to above. Parabolas**

**follow the equation below. **

**
y = X^2/(4*focal)**

**When the focal is .25, y will be one when x is one. **

**This
webpage**** allows a focal point to be entered**

**and it will do all the plotting. **

**Something like a solar cooker might require a focal**

**length more like shown below. **

**When the focal is 1, y will be 0.25 when x is one. **

**So X can be thought of as the radius of the parabola,**

**and y as being the depth. **

**Some applications may want the focal point to be close**

**to one half the depth. **

**Making the focal length equal to sqrt(1/8) will do **

**the job. **

**This same graphing feature can be extended to a web**

**page that can actually ****graph
out the segments**** of **

**the parabola.**

**In this webpage, select a focal length and select**

**whether to plot segments or the parabola sides. **

**The parabola plots x as being step by **

**a consistent amount and the corresponding **

**y values displayed as lines. **

**The web pages have been designed to be able to **

**directly print out the curves on one page. Or **

**they can be ****saved as a pdf file****. **

**Print out three segments and the left and **

**right sides, then construct the parabola. This**

**will show how well everything lines up. All the **

**lines are present for alignment purposes.**

**The segments have been designed to have a consistent **

**spacing in the x direction. The curve of the segments**

**will align themselves with both the x and y lines**

**on the left and right sides. **

**The web page is plotting everything on a 700x700
canvas.**

**Things have been simplified for a one page printout.
Unlike**

**most plotting resources, the x and y are not seeing a
funny**

**auto scale. **

**The plot is for now a bit map. The plot will define
the shape**

**to a focal length relative to a radius. One could
import the**

**plots into an application to do some size scaling. It
should**

**be possible to build any size and shape of a parabola
desired. **