CHAPTER 10. TRIGONOMETRY 10.3
1 − siny− (1− 2 sin^2 y)
2 siny cosy− cosy
=− 1
=⇒
2 sin^2 y− siny
cosy(2 siny− 1)
=− 1
=⇒
siny(2 siny− 1)
cosy(2 siny− 1)
=− 1
=⇒ tany =− 1
=⇒ y = 135◦+ 180◦n; n∈Z
10.3 Applications of Trigonometric Functions
EMCCN
Problems in Two Dimensions EMCCO
Example 5: Problem in Two Dimensions
QUESTION
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A
C B
D
O
θ
x
x
For the figure below, we are given that
CD = BD = x.
Show that BC^2 = 2x^2 (1 + sinθ).