Gus and Lyle's Precalculus Website

Glossary

a

absolute value - The actual value of a number, without regard to its sign. Ex. The absolute value of -5 is 5. This is written as |5| = 5.

c

complex number - A combination of a real number and an imaginary number, expressed in the form a + bi. Ex. 3 + 2𝑖
constant - A value that does not change in an algebraic equation. Ex. The 5 in 2x + 5 is a constant.

e

ellipse - The set of all points (x,y) in a plane, the some of whose distances from two distinct fixed points (foci) is constant.

f

function - A process in which each x value has a single corresponding y value. This can be confirmed on a graph using the vertical line test.

h

hyperbola - The set of all points (x,y) in a plane, the difference of whose distances from two fixed points (foci) is a positive constant.

l

line - A straight, one dimensional figure that stretches on forever in both directions.
line segment - A line with two points as ends.

m

magnitude - The length of a vector.

p

parabola - The set of all points (x,y) in a plane that is equidistant from a fixed line, the directrix, and a fixed point, the focus, not on the line. The midpoint between the focus and the directrix is the vertex and the line passing through the focus and the vertex is the axis of the parabola.
plane - A flat, two dimensional surface that is infinitely large.

s

slope - Measure of a straight line's steepness or slant.

v

variable - A symbol, usually a letter, that represents an unknown value.
vector - A directed line segment with an initial point and a terminal point.

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