Twenty (20) exercises from Cohen whose solutions are due:

8.1   The Addition Formulas, page 584:

11, 13, 21, 33, 49, 51, 55, 77

8.2   The Double-Angle Formulas, page 595:

1, 5, 33, 35, 39, 43, 55, 67

8.3   The Product-to-Sum and Sum-to-Product Formulas, page 603:

( n / a )

8.4   Trigonometric Equations, page 616:

5, 19, 45, 49