8)Write the expression as the sine, cosine, or tangent of an angle

8)Write the expression as the sine, cosine, or tangent of an angle. 
sin(23°)cos(4°) + cos(23°)sin(4°)

9)Find the exact value of the expression.

sin?/6 cos?/3+ cos?/6 sin?/3

10)Find the exact value of the expression.
cos?/16 cos 3?/16 − sin?/16 sin3?/16

11)Find the exact value of the expression.
tan 25° + tan 110°/1 − tan 25° tan 110°
 

12)Find the exact value of the trigonometric expression given that 
sin(u) = − 3/5, where 3?/2 < u < 2?, and cos(v) = 15/17, where 0 < v < ?/2.
sin(u + v)

13)Find the exact value of the trigonometric expression given that 
sin(u) = − 3/5, where 3?/2 < u < 2?, and cos(v) = 15/17, where 0 < v < ?/2.
cos(u + v)

14)Find the exact value of the trigonometric expression given that 
sin(u) = − 3/5, where 3?/2 < u < 2?, and cos(v) = 15/17, where 0 < v < ?/2.
tan(u + v)

15)Find the exact value of the trigonometric expression when 
sin(u) = − 12/13 and cos(v) = − 3/5. (Both u and v are in Quadrant III.)
cos(u + v)

16)Write the trigonometric expression as an algebraic expression.
cos(arccos(8x) − arcsin(8x))

17)Write the trigonometric expression as an algebraic expression.
cos(arcsin(2x) − arctan(6x))

18)Find the solution(s) of the equation in the interval [0, 2?). Use a graphing utility to verify your results. (Enter your answers as a comma-separated list.)
9 cos(x + 7?/6) − 9 cos(x − 7?/6) = −9

x=_____________

19)Find the solution(s) of the equation in the interval [0, 2?). Use a graphing utility to verify your results. (Enter your answers as a comma-separated list.)
8 sin(x + ?/2) + 12 tan(?-6) = 0

x=_____________