Let’s begin our study with products of sin x sin x and cos x. In addition, these types of integrals appear frequently when we study polar, cylindrical, and spherical coordinate systems later. This technique allows us to convert algebraic expressions that we may not be able to integrate into expressions involving trigonometric functions, which we may be able to integrate using the techniques described in this section. They are an important part of the integration technique called trigonometric substitution, which is featured in Trigonometric Substitution. These integrals are called trigonometric integrals. In this section we look at how to integrate a variety of products of trigonometric functions. 3.2.3 Use reduction formulas to solve trigonometric integrals.3.2.2 Solve integration problems involving products and powers of tan x tan x and sec x.3.2.1 Solve integration problems involving products and powers of sin x sin x and cos x.
