Lesson 5.1--Using Fundamental Identities
What you should learn: To recognize and write the fundamental
trigonometric identities. To use the fundamental trig identities to
evaluate trig functions, simplify trig expressions, and rewrite trig
expressions.
Why you should learn it: Fundamental trig identities can be used
to simplify trigonometric expressions.
Pass out Identity Sheet
Using Identities to Evaluate a Function
Example: Use the given values and to find the values of all six trig functions.
Simplifying a Trigonometric Expression
Example: Simplify
Check in calculator
--1s & 0s and
graphing
Factoring Trigonometric Expressions
Example: Factor each expression
Can also check in calculator that factored correctly!
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2
Use Identities to get all the same
trig function
Simplifying Trigonometric Expressions
Example: Simplify Sometimes when
simplifying trig
functions, it is helpful
to write them all in
terms of sine and
cosine.
Adding or Subracting Trigonometric Expressioins
Example: Add
Rewriting a Trigonometric Expression
Example: Rewrite so it is not in fractional form.
HW: p. 463 1, 2, 11, 12, 19, 22, 25, 28, 32, 35, 37, 38, 41, 43, 45, 46, 51, 52
53, 56, 57, 60, 64 = 23 problems
Think of it as
rationalizing the
denominator--no
trig functions in
the denominator
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