19 lines
980 B
Markdown
19 lines
980 B
Markdown
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# Trigonometric Identities
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All of the following only apply when the denominator is not equal to zero.
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$$ tan \theta = \frac{y}{x} $$
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Because the following are inverses of their counterparts, you only need to remember the equivalents for $sin$, $cos$, and $tan$, then just find the inverse by taking $1/v$.
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| Identity | Inverse Identity |
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| ------------------------------- | ------------------------------ |
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| $$ sin\theta = y $$ | $$ csc\theta = \frac{1}{y} $$ |
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| $$ cos\theta = x $$ | $$ sec \theta = \frac{1}{x} $$ |
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| $$ tan\theta = \frac{sin\theta} | |
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$$ cot \theta = \frac{x}{y} $$
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$$ sec\theta = \frac{1}{cos\theta}$$
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$$ csc\theta = \frac{1}{sin\theta}$$
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# Pythagorean Identities
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The Pythagorean identity expresses the Pythagorean theorem in terms of trigonometric functions. It's a basic relation between the sine and cosine functions.
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$$ sin^2 \theta + cos^2 \theta = 1 $$
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