Formulae Flashcards
1
Q
Percentage change
A
Percentage change = (difference / original) x 100
2
Q
Compound interest
A
N = Ni (1 + r/100)^n
3
Q
Nth term of a sequence
A
Un = a + (n-1)d
4
Q
Sum of a sequence where the last term is known
A
Sn = n/2(a + L)
5
Q
Sum of a sequence where the last term is unknown
A
Sn = n/2[a + (n-1)d]
6
Q
Equation of a straight line (3 answers)
A
y = mx + c
ax + by + c = 0
y - y1 = m(x - x1)
7
Q
Area of a circle
A
πr²
8
Q
Circumference of a circle (2 answers)
A
πd
2πr
9
Q
Frequency density
A
Frequency density = frequency / class width
10
Q
Mean
A
Mean = sum of values / number of values
11
Q
Range
A
Range = largest value - smallest value
12
Q
Inter-quartile range
A
IQR = UQ - LQ
13
Q
Direct proportion
A
y ∝ x
y = kx
14
Q
Inverse proportion
A
y ∝ 1/x
y = k/x
15
Q
Probability
A
P = number of specified item / total number of items
