The Trigonometric Functions

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Section 6.1

• The Trigonometric Functions
• aka Transcendental Functions

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Stuff
Trig may seem like Greek to you because we use
Greek letters as variables for angle measures
Remember that an acute angle is between 0 and 90
degrees for now
Also, in a right triangle we think of the sides
in respect to one of the acute angles
hypotenuse
Side opposite
Side adjacent to
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The lengths of the sides of a right triangle
define the six trigonometric ratios.
Do not deliberately mispronounce this one!!
cosecant (csc)
sine (sin)
cosine (cos)
secant (sec)
tangent (tan)
cotangent (cot)
You may want to know these relative positions
and the sequence which they were shown
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The trigonometric Functions of an acute angle in
a right triangle
SOH
CAH
TOA
What was SOHCAHTOAs war cry?
Notice In this arrangement the reciprocals are
horizontally aligned
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Find the 6 trig ratios
0.5
0.4
What if the sides had been 3, 4, 5?
What does this say about similar triangles?
6,8,10?
30, 40, 50?
0.3
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Always rationalize your denominator
You must be able to go forwards and backwards!
Find all six trig ratios.
Given
reciprocal of tan
a2 b2 c2
Hypotenuse
Adjacent 1
Opposite 2
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Trig has lots of identities

• May want trig ID program
• Know reciprocal ID for all six
• Know cofunction IDs for all six

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