Exercises: Exact Trigonometric Values from Special Triangles

Use special triangles and unit circle symmetry. Express all answers in exact form (no decimals).

Grade 9·22 problems·~30 min·Common Core Math - HS Functions·group·hsf-tf-a-3

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Warm-Up: Review What You Know

These problems review skills you have already learned.

$Unit circle with a first-quadrant point P at (a, b), showing horizontal distance a and vertical distance b$

A point $P$ lies on the unit circle at angle $\theta$ . Its coordinates are $(a, b)$ . Which statements are correct?

$\cos\theta = a$ and $\sin\theta = b$

$\cos\theta = b$ and $\sin\theta = a$

$\cos\theta = \frac{a}{b}$ and $\sin\theta = \frac{b}{a}$

$\cos\theta = \frac{1}{a}$ and $\sin\theta = \frac{1}{b}$