Math, Y2 formulas

Question 1

3 Pythagorus theorems

Answer 1

a = [square root] c2 - b2
b = [square root] c2 - a2
c = [square root] a2 + b2

Question 2

3 trigonometry formulas

pls know which button to press on ur calculator

Answer 2

tan […] = o/a
cos […] = a/h
sin […] = o/h

[Hack: TOA CAH SOH]

Question 3

What is the formula to calculate the angle of a right angled triangle (when ur given the length of 2 or more sides) using trigonometry?

Answer 3

e.g. tan-1[angle ABC] = o/a

on ur calculator…just click shift and whatever cosine thing u need then fill in the bracket bit

Question 4

Area of pyramid (optional)

Answer 4

1/3 x BA X h

Question 5

Area of trapezium

Answer 5

a+b/2 x h

Question 6

Area & circumference of circle

Answer 6

Area = πr2
circumference = 2πr / πd (d = diameter)

Question 7

Area of rhombus/ parallelogram

Answer 7

b x h

Question 8

Volume / TSA (total surface area) of cone (given i think)

Answer 8

V = 1/3 πr2h
TSA = πr2 + πrl

Question 9

Volume & TSA of Prism (not tested)

Answer 9

V = BA x h 
TSA = ph = 2BA

Question 10

Direct proportion

Answer 10

y = kx
y/x = k

Question 11

Indirect proportion

Answer 11

yx = k
y = k/x

Question 12

(a + b)2

Answer 12

a2 + 2ab + b2

Question 13

(a - b)2

Answer 13

a2 - 2ab + b2

Question 14

(a + b) (a - b)

Answer 14

a2 - b2

Question 15

(3a + 3b)2 {not tested but good to know}

Answer 15

9 (a + b)2

Question 16

a2 + b2

Answer 16

(a + b)2 - 2ab

Question 17

Find the shortest distance from point A to line BC in this triangle question
[IMPORTANT]

Answer 17

a. Find area of triangle then multiply by 2

b. 2 x (area from ^) ÷ BC = distance/ length