please help!! I have absolutely no idea how to do this!
Write the expression as the sine, cosine, or tangent of an angle.

sin 9x cos x - cos 9x sin x

Question

please help!! I have absolutely no idea how to do this!
Write the expression as the sine, cosine, or tangent of an angle.

sin 9x cos x - cos 9x sin x

anonymous · Answer

the options are
-sin 10x
-cos 8x
-sin 8x
-cos 10x

anonymous · Answer

look up sum formulas for sin and cos

anonymous · Answer

like the identities?

anonymous · Answer

http://www.regentsprep.org/Regents/math/algtrig/ATT14/formulalesson.htm yep

anonymous · Answer

oh and i just noticed that i made the options look like negatives but none of them are  anyways
sin x=1/csc x
cos x=1/sec x
^^ that?

anonymous · Answer

no... have a look at the link i sent

anonymous · Answer

ohh just saw the llink my bad..
ok so where do i go from there?

anonymous · Answer

have a look and see if any match what you have going on and go from there

anonymous · Answer

sin (a-b)=sin a cos b-cos a sin b?

anonymous · Answer

that's what it looks like to me

anonymous · Answer

so it would be sin(9x-x)
so sin 8x
right?

anonymous · Answer

that's what it looks like to me

anonymous · Answer

yayy thank you soo much!!

anonymous · Answer

you're welcome!!!

anonymous · Answer

how can I give you a medal? I am new to this site..

anonymous · Answer

just click on best response, but it's not necessary.  just glad I could help

anonymous · Answer

haha did it anyways thank you again.. Im finally starting to get it a bit more

anonymous · Answer

awesome!  keep at it!