Download Holt McDougal Algebra 2

Fundamental
FundamentalTrigonometric
Identities
Trigonometric Identities
• How do we use fundamental
trigonometric identities to simplify and
rewrite expressions and to verify other
identities?
HoltMcDougal
Algebra 2Algebra 2
Holt
Fundamental Trigonometric
Identities
You can use the fundamental trigonometric
identities to simplify expressions.
Helpful Hint
If you get stuck, try converting all of the
trigonometric functions to sine and cosine
functions.
Holt McDougal Algebra 2
Fundamental Trigonometric
Identities
Using Trigonometric Identities to Rewrite
Trigonometric Expressions
Rewrite each expression in terms of sin θ and cos θ.
Then simplify.
1. sec x (1 – sin2x)


 1 
cos
x
2

 cos x
 cos x 
cos x
Holt McDougal Algebra 2
sin x  cos x  1
2
2
Fundamental Trigonometric
Identities
Using Trigonometric Identities to Rewrite
Trigonometric Expressions
Rewrite each expression in terms of sin θ and cos θ.
Then simplify.
2. sin x cos x (tan x + cot x)
 sin x cos x 


sin xcos x 
 cos x sin x 
2
2
sin x cos x sin x cos x

cos x
sin x
sin x  cos x  1
2
Holt McDougal Algebra 2
2
cos x
sin x
cot x 
tan x 
sin x
cos x
Distributive property
Fundamental Trigonometric
Identities
Using Trigonometric Identities to Rewrite
Trigonometric Expressions
Rewrite each expression in terms of sin θ and cos θ.
Then simplify.
2
2
2
sin
x

cos
x 1
cos x
3.
1  sin x
2
1 sin x
1 sin x
1  sin x 1  sin x 
1 sin x
Holt McDougal Algebra 2
Factor the numerator
 1 sin x
Fundamental Trigonometric
Identities
Using Trigonometric Identities to Rewrite
Trigonometric Expressions
Rewrite each expression in terms of sin θ and cos θ.
Then simplify.
2
2
2
sin
x

cos
x 1
sin x
4.
1  cos 2 x
2
sin x
2
sin x
1
Holt McDougal Algebra 2
Fundamental Trigonometric
Identities
Using Trigonometric Identities to Rewrite
Trigonometric Expressions
Rewrite each expression in terms of sin θ and cos θ.
Then simplify.
2
2
2
1

tan
x

sec
x
sec x  1
5.
1  tan 2 x
tan 2 x
sec 2 x
sin 2 x
2
2
2
sin
x
cos
x
cos x 

2
1
cos
x
1
cos 2 x
Holt McDougal Algebra 2
 sin x
2
Fundamental Trigonometric
Identities
Using Trigonometric Identities to Rewrite
Trigonometric Expressions
Rewrite each expression in terms of sin θ and cos θ.
Then simplify.
sin x
sin 2 x  cos 2 x  1
6.
1  cos x
2
sin x
sin 2 x
1
 csc x
sin x
Holt McDougal Algebra 2
Fundamental Trigonometric
Identities
Lesson 11.3 Practice B
Holt McDougal Algebra 2