Applying and analysing trigonometric functions

• A

• B

• C

• D

sin 2x =

• 2sinx

• 2sinx cosx

• sinx +sinx

 $-4\left(\sin89\degree-\sin167\degree\right)$  

•  $-8\cos128\degree\sin39\degree$  

•  $8\cos128\degree\sin39\degree$  

•  $8\sin128\degree\cos39\degree$  

•  $-8\sin39\degree\sin128\degree$  

 $If\ \cos^{-1}x\ +\cos^{-1}y\ +\ \cos^{-1}z\ =\ 3\pi\$  
then x + y + z is equal to

• 3

• 0

• 6

• -3

Use Sum or Difference Identities to find the exact value of each expression.

cos(75°)

• 1/4

• 
• 
• 

  cos( $\pi$ +x) =

• 0

• cos x

• -cos x

• cos -x