7.1 Trigonometric Identities
Simplifying a Trigonometric Expression
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Factoring-Think of the trigonometric function as the variable.
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Foldable
Steps to Simplifying Trigonometric Identities
1. Be very familiar with all the identities formulas. Some are “commonly used” more
than others. You don’t necessarily need to memorize them all, but you do want to be
able to recognize them quickly.
2. Convert all trigonometric expressions in terms of sinx and cosx. This step is
extremely helpful & important.
3. Simplify each expression in ways you are already familiar with (use what you’ve
learned in Algebra 1 and 2.
a) Cancel out common factors (Factors that lay on top of each other,
cancel each other out).
b) Multiply/Divide fractions (Multiplying –Top by Top & Bottom; Dividing –
Flip the second fraction)
c) Add/Subtract fractions (Get a common denominator and condense
fraction by combining like terms).
d) Simplify complex fractions (by multiplying each “baby fraction” by the
LCD of all the denominators).
REMEMBER – An expression is completely simplified when CAN NOT go any further in
terms of canceling/combing terms.