How do you factor the expression and use the fundamental identities to simplify $(cos^2x-4)/(cosx-2)$ ?

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Answer 1 · 2017-02-05T08:19:28

The answer is $=cosx+2$

We need

$a^2-b^2=(a+b)(a-b)$

Therefore,

$cos^2x-4=(cosx-2)(cosx+2)$

So,

$(cos^2x-4)/(cosx-2)=(cancel(cosx-2)(cosx+2))/cancel(cosx-2)$

$=cosx+2$

How do you factor the expression and use the fundamental identities to simplify (cos^2x-4)/(cosx-2)(cos^2x-4)/(cosx-2)?