Pure Year 1 Unit 9

Question 1

Cosine rule for a missing side

Answer 1

a^2 = b^2 + c^2 - 2bc cos(A)

Question 2

Cosine rule for a missing angle

Answer 2

cos(A) = (b^2 + c^2 - a^2) / 2bc

Question 3

Sine rule for finding missing side

Answer 3

a / sin(A) = b / sin(B) = c / sin(C)

Question 4

Sine rule for finding missing angle

Answer 4

sin(A) / a = sin(B) / b = sin(C) / c

Question 5

Trigonometric formula for area of a triangle

Answer 5

area = 1/2 ab sin(C)