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)#