Trigonometry Examples

Simplify 2cos((7pi)/8)^2-1
Step 1
Apply the cosine double-angle identity.
Step 2
Cancel the common factor of .
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Step 2.1
Factor out of .
Step 2.2
Cancel the common factor.
Step 2.3
Rewrite the expression.
Step 3
Apply the reference angle by finding the angle with equivalent trig values in the first quadrant.
Step 4
The exact value of is .
Step 5
The result can be shown in multiple forms.
Exact Form:
Decimal Form: