sin(30°) Exact Value
sin(30°) = 1/2 exactly.
Problem
Answer
Step-by-step solution
Step 1: Recognize a special angle
30° is a standard position on the unit circle.
Step 2: Read the sine
Sine is the y-coordinate, which equals 1/2.
Why this works
Calculator mode matters: sin(30) in radian mode is not 1/2. Include the degree symbol or convert 30° to π/6 radians. Cosine of 60° is the cofunction partner and is also 1/2.
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Frequently asked questions
Is sin(150°) also 1/2?
Yes. Sine is positive in the second quadrant, and 150° is the supplement of 30°.