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## Pythagorean Identities

Trigonometric identities bring new life to the Pythagorean theorem by re-envisioning the legs of a right triangle as sine and cosine. See more

# Sine and Cosine

What is the value of

$\sin^2 30 ^ \circ + \cos^2 30 ^\circ?$

What is the value of

$\sin^2 \dfrac{\pi}{3} + \cos^2 \dfrac{\pi}{3}?$

If $$\sin \theta = \frac { 1}{3}$$, what is the value of $$\cos^2 \theta$$?

If $$\cos \theta = \frac {\sqrt{3}}{2}$$, what is the value of $$1-\sin^2 \theta$$?

If $$\tan \theta = \frac{3}{4}$$, what is the value of $$\sin^2 \theta + \cos^2 \theta$$?

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