Trig derivatives

[Mackenzie25]

I'm having a lot of trouble with a review sheet that I'm doing on trig derivatives, and although I've been able to solve some of them, there are a few I'm still stuck on. The three that I haven't done are a lot like this one, so I was wondering if anyone could please help me solve? I don't even know where to get started. Thanks in advance- Mackenzie


find y' when y=2sin(3x)cos(4x)

 

[tkhunny]

If y = f(x) * g(x), could you do it using the Product Rule?

 

[Mackenzie25]

I had thought about that, but does the twothat it has create a complication? I don't remember how to do the product rule when there is a constant attatched to one of the functions

 

[tkhunny]

The constant is NOT a complication.

(d/dx)(af(x)g(x)) = a(d/dx)(f(x)g(x))

Of course, with this one, you can also make your life a little easier...

2 * sin(3x) * cos(4x) = sin(3x+4x) + sin(3x-4x)

No more product rule!