Rewriting a trigonometric expression using the difference of squares
Rewrite the trigonometric expression:
Notice that both the coefficient and the trigonometric expression in the first term are squared, and the square of the number 1 is 1. This is the difference of squares. Thus,
There are multiple ways to represent a trigonometric expression. Verifying the identities illustrates how expressions can be rewritten to simplify a problem.
Graphing both sides of an identity will verify it. See
[link] .
Simplifying one side of the equation to equal the other side is another method for verifying an identity. See
[link] and
[link] .
The approach to verifying an identity depends on the nature of the identity. It is often useful to begin on the more complex side of the equation. See
[link] .
We can create an identity by simplifying an expression and then verifying it. See
[link] .
Verifying an identity may involve algebra with the fundamental identities. See
[link] and
[link] .
Algebraic techniques can be used to simplify trigonometric expressions. We use algebraic techniques throughout this text, as they consist of the fundamental rules of mathematics. See
[link] ,
[link] , and
[link] .
Section exercises
Verbal
We know
is an even function, and
and
are odd functions. What about
and
Are they even, odd, or neither? Why?
(mathematics) For a complex number a+bi, the principal square root of the sum of the squares of its real and imaginary parts, √a2+b2 . Denoted by | |.
The absolute value |x| of a real number x is √x2 , which is equal to x if x is non-negative, and −x if x is negative.