1. Lesson 51 – Addition & Subtraction Identities
Math 2 Honors - Santowski
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2. Fast Five True or False (and justify your response)
(a) sin(A + B) = sinA + sinB
(b) cos(A – B) = cosA – cosB
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3. (A) Six New Identities (GASP!!)
Here are six new identities that we call the addition & subtraction identities
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4. (B) Proving Cosine Subtraction Identity
We will prove
We will use our unit circle to do so
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5. (C) Proving Sine Addition Identity
We will prove
We will use right triangle trig to do so
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6. (D) Proving Tan Addition Identity
You will prove
You will use fundamental trig identities to do so
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7. (E) Using the Addition/Subtraction Identities
Determine the exact value of sin(15º)
Determine the exact value of cos(-195º)
Determine the exact value of
Determine the exact value of tan(255º)
If sin(a) = -4/5 for 180º<a<270º and if cos(b) = -5/13 for 90º<b<180º, evaluate tan(a+b)
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8. (E) Using the Addition/Subtraction Identities
We can use the new identities to develop new identities:
Prove the following: (describe each identity from a transformations perspective as well as a unit circle perspective)
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9. (E) Using the Addition/Subtraction Identities
Prove the following:
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10. (E) Using the Addition/Subtraction Identities
We can use the new identities to develop new identities:
Develop a new identity for:
(a) sin(2x)
(b) cos(2x)
(c) tan(2x)
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11. (F) Homework S14.4, p914, Q11,13,25,27,33-44all,67,77,78 7/6/2018
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