Plane Analytic Geometry

This section reviews the most common 2 dimensional curves:

the line, circle, ellipse, parabola, and hyperbola.

You need to be familiar with the equation for each. Later in the course, you’ll need to be able to generate, for example, the equation for a circle as a step in solving a more complex problem.

Line

You should be familiar with the standard form of the equation for the straight line:

y = mx + b

where m is the slope of the line and b is the y-intercept (where the line crosses the y axis).

Here is the equation y = 3x + 2:

Note that the slope is positive, +3, moving upward. It crosses the y axis at y = 2.

Look at the curve below. What is its slope?

The slope is 2.

What is its y-intercept?

The y-intercept is -1.