Everything Maths Grade 11

17.5 CHAPTER 17. TRIGONOMETRY

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(1.) 0153 (2.) 0154 (3.) 0155 (4.) 0156

Summary of the Trigonometric

Rules and Identities

EMBDQ

Squares Identity Quotient Identity

cos^2 θ + sin^2 θ = 1 tan θ =sincos θ θ

Odd/Even Identities Periodicity Identities Cofunction Identities

sin(−θ) =−sin θ sin(θ± 360 ◦) = sin θ sin(90◦− θ) = cos θ

cos(−θ) = cos θ cos(θ± 360 ◦) = cos θ cos(90◦− θ) = sin θ

Sine Rule Area Rule Cosine Rule

Area =^12 bccos A a^2 = b^2 + c^2 − 2 bccos A

sin A

a =

sin B

b =

sin C

c Area =

1

2 accos B b

(^2) = a (^2) + c (^2) − 2 accos B
Area =^12 abcos C c^2 = a^2 + b^2 − 2 abcos C
Chapter 17 End of Chapter Exercises
Q is a ship at a point 10 km due South of another ship P. R is a
lighthouse on the coastsuch thatPˆ =Qˆ = 50◦.
Determine:
(a) the distance QR
(b) the shortest distancefrom the lighthouse to the line joining the
two ships (P Q).
10 km
P
Q
R
50 ◦
50 ◦