Term

Definition

abscissa 
the x value of a coordinate (x, y) 
absolute maximum 
the highest point on a curve within the natural or given domain 
absolute minimum 
the lowest point on a curve within the natural or given domain 
absolute value 
the absolute value makes a negative number positive, leaving positive numbers or zero unchanged. The absolute value of 2, expressed as 2 = 2. The ‘lines’ about the number are called modulus. x would be called absolute x 
acceleration 
the rate of change of velocity over time. Acceleration, often expressed as , is the first derivative of the velocity function, or the second derivative of the displacement function 
acute angle 
also known as sharp angle. Angle less than 90° in magnitude 
acute triangle 
triangle with all three angles less than 90° 
adjacent 
next to 
adjacent angles 
two angles which share a common vertex and side ∠a and ∠b are adjacent angles

algebra 
maths using letters or symbols (pronumerals) as well as numbers 
algorithm 
set of instructions to solve a problem. An example of a very simple algorithm: 2 + 3, the plus sign instructs us to add the two numbers, giving us an answer of 5 
alpha 
α Greek letter for a, commonly used to indicate unknown angles 
alternate angles 
alternate angles in parallel lines are equal and form a “z” shape

altitude 
perpendicular height 
am 
time after midnight and before midday, the morning (antimeridian) 
amplitude 
the height between the centre of a periodic function and its maximum height. The amplitude of y = sin x and y = cos x is 1

analogue clock 
clock with hands that rotate around the face to show the time (opposite to digital clock) 
angle 
the measurement of the size of ‘turn’ between two lines 
angle of depression 
the angle from the horizontal looking down

angle of elevation 
the angle from the horizontal looking up

angle sum of polygon 
angle sum of any polygon = (n – 2) x 180°, where n is the number of sides in the polygon 
annual 
per year 
annulus 
the area between concentric circles. The formula to find the annulus is
A = π(R^{2} – r^{2}) or A = πR^{2} – πr^{2}

annum 
year 
anticlockwise 
opposite direction a clock moves. Anticlockwise would be a circular movement to the left, rather than the right 
antiderivative 
the primitive or integral of a function 
apex 
the top of a shape, the highest point 
approximate 
to estimate or guess the number, not do exact calculations 
arc 
the part of a circle’s circumference

arc length 
ℓ= πr 
area 
the region bounded inside a shape 
arithmetic progression 
a sequence of numbers that have a common difference.
eg: 1, 5, 9, 13…. all have a difference of 4 
arithmetic series 
a sequence of numbers with a common difference that are being added.
eg: 1 + 5 + 9 + 13 + …. 
ascending 
going up, ascending order means going from smallest to largest. 
asymptote 
a number or a line that is never quite reached. A curve is said to be asymptotic if it approaches a value, but never actually touches it. 
average 
or mean, expressed often as . To calculate the average of a set of numbers, add up all of the numbers and then divide by how many numbers there are. example: the average of 1, 2 ,4, 5 and 8 would be $$\frac{1 + 2 + 4 + 5 + 8}{5}=\frac{20}{5}$$= 4 
axis of symmetry 
the line dividing a shape or function exactly in half so that it is the same on both sides, a mirror image 
axis of symmetry of a parabola 
$$x=\frac{b}{2a}$$ 