TRIGONOMETRY Proving Trigonometric Identities
REVIEW Quotient Identities Reciprocal Identities Pythagorean Identities
Let’s start by working on the left side of the equation….
Rewrite the terms inside the second parenthesis by using the quotient identities
Simplify
To add the fractions inside the parenthesis, you must multiply by one to get common denominators
Now that you have the common denominators, add the numerators
Simplify
Since the left side of the equation is the same as the right side, you’ve successfully proven the identity!
On to the  next problem….
Let’s start by working on the left side of the equation….
We’ll factor the terms using the difference of two perfect squares technique
Using the Pythagorean Identities the second set of parenthesis can be simplified
Since the left side of the equation is the same as the right side, you’ve successfully proven the identity!
On to the  next problem….
Let’s start by working on the right side of the equation….
Multiply by 1 in the form of the conjugate of the denominator
Now, let’s distribute in the numerator….
…  and simplify the denominator
‘ Split’ the fraction and  simplify
Use the Quotient and Reciprocal Identities to rewrite the fractions
And then by using the commutative property of addition…
…  you’ve successfully proven the identity!
One more….
Let’s work on the left side of the equation…
Multiply each fraction by one to get the LCD
Now that the fractions have a common denominator, you can add the numerators
Simplify the numerator
Use the Pythagorean Identity to rewrite the denominator
Multiply the fraction by the constant
Use the Reciprocal Identity to rewrite the fraction to equal the expression on the right side of the equation

Proving Trigonometric Identities