There are a few different ways to calculate focal diameter. For example, you can find it by dividing x2 by 4p. Another way is to divide x2 by -13y. You can also find it by measuring the length of the focal chord. A focal chord has four points, and they are called the A and B points.

## x2 = 4py

When calculating a focal diameter, you want to know exactly how far the focus is from the center of the lens. You can use x2=4py to find this out. In this example, the focus is located at (0,p) and the focus distance is 45 meters.

This equation is a parabola and it can be interpreted in many ways. A parabola can be used as a reflector, an ellipse, a telescope, or as an architectural structure. It’s very useful for analyzing how a lens works.

A parabola’s focal diameter is the line segment that passes through the focus. If this line segment is parallel to the directrix, then it will lie on the parabola. Solving these equations will give you the focal diameter of a parabola.

## x2 = -13y

You can find the focal diameter of a lens by finding the distance between the p-axis and a point with x2 = -13y. You can also find the diameter of a ring by finding the distance between the x-axis and the focus.

The focal diameter of a ring depends on the focus and the angle of the tangent to the x-axis. If you know the focal diameter, you can use a parabola equation to find the focal diameter. The equation for a parabola is given below.

If x-axis lies on the focus, then x2 = -13y gives you the focal diameter. A circle with radius r will have a diameter of x2 = -13y. The formula for focal diameter can be applied to any circle.