Trigonometry Examples

cos (3 π)

$\cos (3 π)$

Step 1

Subtract full rotations of

2 π

$2 π$ until the angle is greater than or equal to

0

$0$ and less than

2 π

$2 π$ .

cos (π)

$\cos (π)$

Step 2

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.

- cos (0)

$- \cos (0)$

Step 3

The exact value of

cos (0)

$\cos (0)$ is

1

$1$ .

- 1 \cdot 1

$- 1 \cdot 1$

Step 4

Multiply

- 1

$- 1$ by

1

$1$ .

- 1

$- 1$

$\cos 3 π$

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√

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≥

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≤

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