Posted by **Belden** on Saturday, April 5, 2008 at 12:27am.

1. Find the value of Sin^-1(-1/2)

a. -30 degrees

b. 30 degrees

c. 150 degrees

d. 330 degrees

2. Find the exact value of cos(-420 degrees)

a. -1/2

b. 1/2

c. sqrt of 3/2

d. -sqrt of 3/2

3. p(-9/41, 40/41) is located on the unit circle. Find sin theta.

a. 40/41

b. -9/41

c. -9/40

d. -40/9

4. In triangle ABC, C = 60 degrees, a=12, and b=5. Find c.

5. Which triangle should be solved by beginning with the law of Cosines?

a. A=115 degrees, a=19, b=13

b. A=62 degrees, B=15 degrees, b=10

c. B=48 degrees, a=22, b=5

d. A=50 degrees, b=20, c=18

- Math -
**drwls**, Saturday, April 5, 2008 at 1:09am
1. Both a and d are correct. -30 and 330 degrees are the same angle

2. d

3. b theta = sin^-1 (-9/41)/1, siunce it is on a unit circle.

Note that sqrt[(-9/41)^2 + (40/41)^2] = 1

4. Use the law of cosines when you know two adjacent sides and the included angle (which would have a capital letter designation different from the sides). Only one of the choices fits this criterion.

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