# Required Formulas Flashcards

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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

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

A

ax^2 + box + c = 0

16
Q

Equation of a straight line

A

y= mx + c

17
Q

Sum of interior angles

A

(x-2) x 180

18
Q

A

Change in y

Change in x

19
Q

Area of a sector

A

θ/360 x π x r^2

20
Q

Arc length

A

θ/360 x 2 x π x r

21
Q

Geometric sequence (nth term)

A

Xn= n^multiplier

22
Q

Fibonacci’s sequence

A

Xn= sum of the previous two numbers

23
Q

Cone surface area

A

πrl + πr^2

24
Q

Percentage increase

A

(new price- original price) / original price