Download Sum and Difference Identities Practice

NAME _____________________________ DATE _______________ PERIOD ________
7-3
Practice
Sum and Difference Identities
Use sum or difference identities to find the exact value of each trigonometric
function.
5p
}
1. cos }
12
2. sin (21658)
3. tan 3458
4. csc 9158
7p
}
5. tan 12}
12 2
p}
6. sec }
12
p
} and 0 , y , }} .
Find each exact value if 0 , x , }p
2
2
7. cos (x 1 y) if sin x 5 }15}
and sin y 5 }45}
3
8. sin (x 2 y) if cos x 5 }18}
and cos y 5 }35}
7
9. tan (x 2 y) if csc x 5 }153} and cot y 5 }43}
Verify that each equation is an identity.
10. cos (1808 2 u) 5 2cos u
11. sin (3608 1 u) 5 sin u
12. Physics Sound waves can be modeled by equations of the
form y 5 20 sin (3t 1 u). Determine what type of interference
results when sound waves modeled by the equations
y 5 20 sin (3t 1 908) and y 5 20 sin (3t 1 2708) are combined.
(Hint: Refer to the application in Lesson 7-3.)
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Advanced Mathematical Concepts