October 23, 2014
IB Math Studies SL
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Pg 119 # 1 – 7
Review Multi-Step Trig. Problems Worksheet
from Tuesday.
Also Review P.108-109 Problems
◦ Pg 112-113
◦ TEST ON Chapter 3 Section 3
◦ Rm A108

Sine Function: sin(θ) = Opposite / Hypotenuse

Cosine Function:

Tangent Function: tan(θ) = Opposite /
Hypotenuse
Adjacent
cos(θ) = Adjacent /
How to remember? Think "Sohcahtoa"!
 It works like this:
SOH...
Sine = Opposite / Hypotenuse

CAH...
TOA…
Cosine = Adjacent /
Hypotenuse
Tangent = Opposite / Adjacent

In picture form:

ghj
Now lets turn to page 104 in your Oxford
Book. Refer to Example 9


Pythagorean theorem used to find the
missing side first
a2 + b2 = c2
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Using this triangle (lengths are only to one
decimal place):sin(35°) = Opposite /
Hypotenuse
= 2.8 / 4.9
= 0.57...

Sine, Cosine, and Tangent Practice
Worksheet (page 1 and 2)
HOMEWORK pages 106 – 107 # 1 - 4
Monday, Nov. 3, 2014
SINE RULE (119)
sin 𝐴 sin 𝐵
=
𝑎
𝑏
=

OR
sin 𝐶
𝑐

𝑎
𝑏
=
sin 𝐴 sin 𝐵
=
𝑐
sin 𝐶

*2 angles and 1 side
*2 sides and 1 non
included angle
COSINE RULE (121)
(Find the sides use)
𝒂𝟐 = 𝒃𝟐 + 𝒄𝟐 - 2bc cos A
𝒃𝟐 = 𝒂 + 𝒄𝟐 - 2ac cos B
𝒄𝟐 = 𝒂𝟐 + 𝒃𝟐 - 2ab cos C
(Rearranged for angles)
𝒃𝟐 +𝒄𝟐 − 𝒂𝟐
Cos A =
𝟐𝒃𝒄
𝒂𝟐 +𝒄𝟐 − 𝒃𝟐
Cos B =
𝟐𝒂𝒄
𝟐
𝒂 +𝒃𝟐 − 𝒄𝟐
Cos C =
𝟐𝒂𝒃
*2 sides and 1 included angle
* 3 sides no angles
𝟏
𝟐

Area of Triangle:

Example 5 p. 125



Area =
1
2
(2 sides) sin (Included Angle)
(7)(12) sin 82
Area = 42 (0.9903)
Area = 41.6𝑘𝑚2
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Classwork
Page 121 # 1 b,c -3
Page 123 # 1b,c- 3
Page 126 # 1 - 4
Due In Class Today
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


Homework
Page 121 # 4- 8
Page 123-124 # 4 – 9
Page 127 # 5 – 7(top)
Due on Mon Nov 10, 2014