Maths Dictionary

 
acceleration
The acceleration of an object measures the rate of change in its velocity. We use the second derivative [ f ''(t)] to calculate this. 
acute angle
An angle between 0o and 90o.
addition rule (probability)
P(A or B) = P(A) + P(B) – P(A and B)
We can use this for all types of events. However, if the events are mutually exclusive, we do not need the “ –  P(A and B)” part. This is because P(A and B) = 0 for mutually exclusive events.
additive inverse
When a number is added to its additive inverse the answer is zero.
adjacent angles
Two angles are adjacent if they share the same vertex and have one side in common between them.
algebraic expression
An expression made up of any number of terms seperated from each other by + an -.
algebraic fraction
A fraction which contains variables.
alternate angles
When lines are parallel, we have equal alternate angles. Look for a Z or a N.
alternating series
This is a series in which every term has the opposite sign from the preceding term.
e.g. 1 - 3 + 5 - 4 + 9 . . .
altitude
Perpendicular height of a shape. A triangle has three altitudes.
analitical geometry
This is the branch of mathematics that uses algebra to help in the study of geometry.
angle of depression
Measured from the horizontal downwards.
angle of elevation
Measured from the horizontal upwards.
apex
This is the pointed tip of a cone or pyramid.
arc of a circle
An arc is part of the circumference of a circle.
area
The amount of surface or the size of a surface, measured in square units.
arithmetic sequence
Sequences with a constant first difference i.e. you need to add or subtract the same amount to get the next term.
(e.g.  5 ; 1 ; -3 ; -7 ; . . . )
arithmetic series
You get this when you add the terms of an arithmetic sequence.
(e.g. 5 + 1 - 3 - 7 - . . .)
ascending order
From smallest to biggest.
asymptote
A straight line which a graph approaches, but never reaches. In the example below, we have a horizontal asymptote.
axiom
A mathematical fact that is accepted to be true without needing to prove it.
e.g.  a tangent to a circle is perpendicular to a radius of that circle, at the point of contact
axis of symmetry
The line which divides a shape (or graph) so that one half is the mirror image of the other half.