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.

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


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"


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

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

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.