9.4E: Sum-to-Product and Product-to-Sum Formulas (Exercises)
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For the following exercises, evaluate the product for the given expression using a sum or difference of two functions. Write the exact answer.
30. cos(π3)sin(π4)
31. 2sin(2π3)sin(5π6)
32. 2cos(π5)cos(π3)
For the following exercises, evaluate the sum by using a product formula. Write the exact answer.
33. sin(π12)−sin(7π12)
34. cos(5π12)+cos(7π12)
For the following exercises, change the functions from a product to a sum or a sum to a product.
35. sin(9x)cos(3x)
36. cos(7x)cos(12x)
37. sin(11x)+sin(2x)
38. cos(6x)+cos(5x)