Trigonometry Examples

Find the Exact Value 3cos(120)
Step 1
Apply the reference angle by finding the angle with equivalent trig values in the first quadrant. Make the expression negative because cosine is negative in the second quadrant.
Step 2
The exact value of is .
Step 3
Multiply .
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Step 3.1
Multiply by .
Step 3.2
Combine and .
Step 4
Move the negative in front of the fraction.
Step 5
The result can be shown in multiple forms.
Exact Form:
Decimal Form:
Mixed Number Form: