A

**abscissa: x-coordinate. The abscissa of the point ( a, b) is
a.**

**absolute value: the distance of a number from zero. The positive
value.**

**acceleration: the rate of change of velocity. If position is represented
by s(t), then velocity
is s'(t) and acceleration is s"(t).**

**acute angle: a positive angle that measures less
than 90 degrees.**

**acute triangle: a triangle each of whose angles measures
less than 90 degrees.**

**additive identity: The number zero is called the additive
identity because when you add it **

** to
a number, N, the result you get is the same number, N.**

**additive inverse: the additive inverse of a number, N,
is the number that when you add it **

** to
N, the result that you get is zero. The additive inverse of
7 is -7. **

** The additive inverse of -3 is 3.**

**adjacent angles: two angles that share both a side and a vertex.**

**altitude: the perpendicular distance from the base of
a figure to the highest point of the **

** figure.
**

**amplitude: half the difference between the largest and
smallest function value of a **

** periodic
function.**

**angle: the union of two rays with a common endpoint.**

**antecedent: the hypothesis of conditional statement. The
"if" part of an "if-then" **

** statement.**

**antiderivative: the antiderivative of a function, f(x),
is a function, F(x), whose derivative is **

** f(x).
Also called the indefinite integral.**

**apothem: the perpendicular distance from the center to
a side of a regular polygon.**

**arc: the set of points on a circle that lie in the interior
of a central angle.**

**arc length: s = integral (sqrt (1 + (dy/dx) ^{2}))
dx.**

**arccos: If x = cos y, then y = arccos x. The inverse
of the cosine function.**

**arccsc: If x = csc y, then y = arccsc x. The inverse
of the cosecant function.**

**arccot: If x = cot y, then y = arccot x. The
inverse of the cotangent function.**

**arcsec: If x = sec y, then y = arcsec x. The
inverse of the secant function.**

**arcsin: If x = sin y, then y = arcsin x. The
inverse of the sine function.**

**arctan: If x = tan y, then y = arctan x. The
inverse of the tangent function.**

**argument: The independent variable in a function.**

**arithmetic mean: The sum of a set of numbers divided by
the number of numbers. Also **

** called
the average.**

**arithmetic sequence: a sequence of numbers of the form**

* a, a + b, a +
*2*b, a + *3*b, ... , a + *(*n - *1)*b*

**arithmetic series: the sum of an arithmetic sequence.**

**associative property of addition: ( a + b) +
c = a + (b + c)**

**associative property of multiplication: ( a * b)
* c = a * (b * c)**

**asymptote: a straight line that is a close approximation to
a curve as the curve goes off**

**to infinity.**

**average: same as arithmetic mean.**

**axiom: a statement that is assumed to be true without
proof. Postulate.**

**axis of symmetry: a line that passes through a figure
in such a way that the part of the **

** figure
on one side of the line is a mirror reflection of the part of the **

** figure
on the other side of the line.**