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

Question

A)109.0
B)10.4
C)11.8
D)15.1
I chose B

2)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
I chose A

3)P(-9/40,40/41) is located on the unit circle. Find sin theta.
A)40/41
B)-9/41
C)-9/40
D)-40/9
I chose A

4)Find the exact value of cos(-420)
A)-1/2
B)1/2
C)square root of 3 over 2
D)square root of -3 over 2
I chose B

5)Write the equation sin y= x in the form of an inverse function.
A)y=Sin-1x
B)x=Sin-1y
C)y=Sin-1x
D)y=Sinx
I chose A

Answer 1

2,3 are wrong.
On 5, what is the difference between a, c?

Answer 2

the only diff is c has sin-1x and a has Sin-1x

Answer 3

how is 2 not A? my book says to solve an oblique triangle: two angles and any side, and two sides and an angle opposite one of them is solved by Law of Sines. Two angles and their included angle or three sides are solved by Law of Cosines.

Answer 4

<Two angles> and their included angle or three sides? I think that should be <two sides>, then angle C is the one included by sides a and b. That's why answer A is wrong.

Answer 5

help with laws of sines