Intermediate Algebra (11th edition)

universal constant The number e is
called a universal constant because of its
importance in many areas of mathematics.
(Section 10.5)

variable A variable is a symbol, usually a
letter, used to represent an unknown number.
(Section 1.1)

vary directly (is directly proportional to)
yvaries directly as xif there exists a nonzero
real number (constant) ksuch that.
(Section 7.6)

vary inversely yvaries inversely as xif
there exists a nonzero real number (constant)
ksuch that. (Section 7.6)

vary jointly If one variable varies as the
product of several other variables ( possibly
raised to powers), then the first variable is said
to vary jointly as the others. (Section 7.6)

vertex The point on a parabola that has the

leasty-value (if the parabola opens up) or the

greatest y-value (if the parabola opens down) is

called the vertex of the parabola. (Section 9.5)

vertical asymptote A vertical line that a

graph approaches, but never touches or

intersects, is called a vertical asymptote.

(Section 7.4)

vertical line test The vertical line test states

that any vertical line will intersect the graph of

a function in at most one point. (Section 3.5)

whole numbers The set of whole numbers

is. (Section 1.1)

x-axis The horizontal number line in a rec-

tangular coordinate system is called the

x-axis. (Section 3.1)

x-intercept A point where a graph inter-

sects the x-axis is called an x-intercept.

(Section 3.1)

y-axis The vertical number line in a rec-

tangular coordinate system is called the

y-axis. (Section 3.1)

y-intercept A point where a graph inter-

sects the y-axis is called a y-intercept. (Sec-

tion 3.1)

zero-factor property The zero-factor prop-

erty states that if two numbers have a product

of 0, then at least one of the numbers must

be 0. (Sections 6.5, 9.1)

Z

Y

X

5 0, 1, 2, 3, 4,Á 6

W

y=kx

y=kx

V

Glossary G-7