I was wondering if someone could help me with this question.. i have absolutely no idea on how to answer it..
2sin(4x)cos(4x)cos(7x)-(cos^2(4x)-sin^2(4x))sin(7x)
please show steps..
You need to review common trig identities thoroughly. I don't mean that as an insult but as advice. Take a look at sum and difference formulas for sin and cos and double angle formulas.
sin(a-b)=sin(a)cos(b)-sin(b)cos(a)
That is the identity you need to finish.