Trig
posted by Scott on .
How do I simplify this?
cos4xcos3xsin4xcos3x
I pulled the cos3x out as a common factor but that doesn't really help. Can someone please direct me on this. Thanks!

Are you sure is isn't
cos4x*cos3x  sin4x*sin3x ?
That would be cos 7x.
If not, then
cos4x*cos3x  sin4x*cos3x
= cos 3x (cos 4x  sin 4x)
= cos 3x [8 cos^2x 8cos^2 x +1  8 cos^3 x sinx + 4 cos x sin x)]
That is not a simplification.
There may have been a typo error in your problem assignment. 
Thanks a lot. I also thought the question was written improperly but I spent a lot of time trying to simplify the darn thing! Thanks for your help.