MATH DICTIONARY

C

cartesian coordinates:   a system whereby points on a plane are identified by an ordered

pair of numbers, representing the distances to two or three perpendicular axes.

center:   the point that is the same distance from all the points on a circle.   The point that

is the same distance from all the points on a sphere.   The point inside an ellipse

where the major and the minor axes intersect.   The center of a circle that can be

inscribed in a regular polygon.

center of mass:  centroid.

central angle:   an angle that has its vertex at the center of a circle.

centroid:  the center of mass of an object.  The point where the object would balance if

supported by a single support.   The point in a triangle where the three medians intersect.

chain rule:  dy/dx = dy/du * du/dx.

chord:  a line segment that connects two points on a curve.

circle:   the set of points in a plane that are a fixed distance from a given point.

circular functions:  same as trigonometric functions.

circumcenter:  the point in a triangle that is the center of the circle that can be

circumscribed about the triangle.   The intersection of the perpendicular

bisectors of the triangle.

circumference:  the distance around a closed curve.  The circumference of a circle is

2*pi*r where r is the radius of the circle.

circumscribed circle:  a circle that passes through all of the vertices of a regular polygon.

closed interval:  an interval that contains its endpoints.

coefficient:  a constant that multiplies a variable.  In Ax + By = C, A and B are coefficients

of x and y.

cofunction:   the cofunction of a trigonometric function, f(x), is equal to f(pi/2 - x).  The

cofunction of the sine is the cosine.   The cofunction of the secant is the

cosecant.  The cofunction of the tangent is the cotangent.

collinear:  points are collinear if they lie on the same line.

commutative property:  a + b = b + a.   a*b = b*a.

complementary angles:  two angles are complementary if their sum is 90 degrees.

completing the square:  the method of adding an expression to both sides of an equation so

that one side becomes a perfect square trinomial.

complex fraction:   a fraction that contains a fraction in its numerator and/or denominator.

complex number:   the sum of an imaginary number and a real number written in the form

a + bi or r(cos x + isin x).

component:  the components in the vector (a, b, c) are a, b, and c.

composite function:  a function that consists of two functions arranged in such a way that

the output of one function becomes the input of the other function.

composite number:   a natural number that is not prime.

concave:  a figure is concave if a line segment can be drawn so that it goes in, out, then

back into the figure.

conclusion:  the part of an if - then statement that follows the word "then".   Consequent.

conditional statement:  an if - then statement.

cone:  the union of all line segments that connect a point and a closed curve in a different

plane from the point.

congruent:   shapes or angles are congruent if you could put one on top of the other, and

they would look like just one shape.   Equal.

conic section:  parabola, hyperbola, ellipse, circle.   Formed by the intersection of a plane

with a right circular cone.

conjecture:   a statement that seems to be true, but has not yet been proven.

conjugate:   the conjugate of a complex number is formed by reversing the sign on the

imaginary part of the number.   The conjugate of a + bi is a - bi.

conjunction:   a statement that is really two statements joined by the word AND.   Both

parts must be true for the statement to be considered true.

consequent:  the part of an "if - then" statement that follows the "then".   Conclusion.

constant:   a value that does not change.

continuous:   a function is continuous if you can draw it without lifting your pencil off the

paper.   y = f(x) is continuous at a if

1.  f(a) exists.

2.  lim as x-->a f(x) exists.

And

3.  lim as x-->a of f(x) = f(a).

contrapositive:  the contrapositive of A-->B is Not B---->Not A.

convergent series:  an infinite series that has a finite sum is called convergent.

converse:   the statement made by interchanging the hypothesis and the conclusion of a

statement.

convex:   a set of points such that for any two points in the set, the line segment that

connects them is also in the set.

coordinates:   a set of numbers that identifies the location of a point.

coplanar:   points that lie within the same plane are called coplanar.

corollary:   a statement that can be easily proven once a theorem is proved.

cosecant:   csc x = 1/sin x

cosine:   In a triangle, the cosine of an angle =   (length of the adjacent side)/(hypotenuse)

cotangent:   cot x = 1/tan x

coterminal angles:  angles whose measures are 2kpi apart.

counting numbers:  natural numbers.  The numbers you use to count.

critical point:  the point on a curve where the first derivative equals zero.  Extremum.

cube:   a solid figure with six square faces.

cubic:  a polynomial of degree 3.

cylinder:  the union of all line segments that connect corresponding points on congruent

circles in parallel planes.

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