14.3a.notebook
March 28, 2012
1. Write a sine function that has a minimum of 3 at x = 3 and a maximum of 4 at x = 9.
Trig Identities
Reciprocals
Recall: secθ = cscθ = cot θ =
Quotient
tan θ = cot θ= 1
14.3a.notebook
March 28, 2012
1. Write an equivalent expression.
a) (cscx)(tanx)
b)
c) cosA(cscA + secA)
Practice: Rewrite as a single fraction.
cscA + 1
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14.3a.notebook
March 28, 2012
Cofunctions
Cofunctions have the same value if their angles are complementary....must add to 90.
*Look for the "co" to identify
sinθ = cos(90 ­ θ)
cosθ = sin(90 ­ θ)
tan θ = cot(90­ θ)
cot θ = tan(90 ­ θ)
secθ = csc(90 ­ θ)
cscθ = sec(90 ­ θ)
1. Solve for A.
a) cos 67o = sin A
o
b) tan17 10' = cot A
c) sec(A + 10) = csc( A ­ 18)
2. If sin A = .4 then cos(90 ­A) = 3
14.3a.notebook
March 28, 2012
Practice:
1. If sin x = cos x, what is the value of x?
2. If tan(x ­ 10) = cot (4x), find x.
3. If sec x = csc 30, find sec x.
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14.3a.notebook
March 28, 2012
Journal: Explain what is true if two functions are cofunctions.
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