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Mathematics 13 Online
OpenStudy (anonymous):

Rewrite with only sin x and cos x. sin 2x - cos x

OpenStudy (anonymous):

sin(2x) = 2sinx cosx 2sinx cosx - cosx

OpenStudy (anonymous):

Here is a double angle formula for sinx\[\sin2x=2sinxcosx\]that will allow you to eliminate the (2x) inside the sine function

OpenStudy (primeralph):

This ^^.

OpenStudy (anonymous):

i don't understand how to do it though .

OpenStudy (primeralph):

Just replace sin(2x) with 2sin(x)cos(x).

OpenStudy (primeralph):

They are equivalent.

OpenStudy (anonymous):

2 sin x cos2x sin x cos x (2 sin x - 1) 2 sin x

OpenStudy (anonymous):

those are my answer choices

OpenStudy (primeralph):

Simplify the result given earlier.

OpenStudy (anonymous):

i don't know how to......

OpenStudy (anonymous):

As xxferocixx said above, once you make the substitution for sin(2x), you get 2sinx cosx - cosx in which both terms have cosx in common... try factoring it out. What do you get?

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