Cosine of a Sum or Difference Worksheet with Answer Key

What's on the worksheet

1. Find the exact value of each by writing the angle as a sum or difference of two angles with known values.
   \cos 75^\circ\cos 195^\circ\cos\dfrac{11\pi}{12}\cos\dfrac{23\pi}{12}
2. Write each as a single cosine.
3. Angle a is in standard position, and the point (−48, 14) lies on its terminal side.
4. Angle a has a = 2 with π < a < 3π2, and angle b has b = 3 with 3π2 < b < 2π.
5. Points P and Q lie on the circle of radius 6 centered at the origin, P at angle 165° and Q at angle 120° in standard position.
6. Put a = b = t in the difference formula for cosine.