# Required Formulas Flashcards

1

Q

Compound Growth/ Decay (Compound interest)

A

N= N₀(multiplier)ⁿ amount after X years= initial amount x (percentage change)^years

2

Q

Area of a trapezium

A

1/2(a+b)h average of parallel lines x vertical height

3

Q

Quadratic equation

A

4

Q

Pythagoras’ Theorem

A

a^2+b^2 = c^2

5

Q

Sine rule

A

6

Q

Cosine rule (sides)

A

7

Q

Cosine rule (angles)

A

8

Q

P(A u B)

A

P(A) + P(B) - P(A n B) Elements in both sets including intersection

9

Q

P(A n B)

A

P(A) x P(B given A) = P(A) x P(B \ A) Intersection of the 2 sets

10

Q

Area of a triangle

A

1/2 a b sinC

11

Q

P (A u B) in a mutually exclusive set

A

P(A) + P(B)

12

Q

Mean in a frequency table

A

Σfx / Σf

f= the midpoint

13

Q

Cone volume

A

1/3 π r^2 h

14

Q

Sphere volume

A

4/3 π r^2

15

Q

Quadratic equation

A

ax^2 + box + c = 0