Question #9d54d

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Answer 1 · 2017-08-26T17:05:55

$- tan(theta)$

We have: $sec(theta) cdot (- sin(theta))$

$= - sin(theta) sec(theta)$

Let's apply the standard trigonometric identity $sec(theta) = frac(1)(cos(theta))$ :

$= - sin(theta) cdot frac(1)(cos(theta))$

$= - frac(sin(theta))(cos(theta))$

Then, let's apply the standard identity $tan(theta) = frac(sin(theta))(cos(theta))$ :

$= - tan(theta)$