Unable to differentiate $\cos(x) \cos(2x) \cos(3x)$ and $\sqrt{\frac{(x-1)(x-2)}{(x-3)(x-4)(x-5)}}$ I apologize for the lack of LaTeX. I will update this question with the proper LaTeX as soon as possible.
I am having trouble with two differentiation exercise questions and was hoping someone could provide a hint in the right direction.
The two questions are: Differentiate
$$\cos(x) \cos(2x) \cos(3x)$$
and
$$\sqrt{\frac{(x-1)(x-2)}{(x-3)(x-4)(x-5)}}$$
Any hint in the right direction is highly appreciated.
Note: Please try to provide the hint towards a logarithmic approach as this was in the logarithms exercise. Also please provide only a hint, not the full answer. I'm hoping to savor some of the glory of mastering a half-tamed beast myself.

Hint
Suppose that you have $$A=f(x)\times g(x)\times h(x)$$ So, using logarithms, you have $$\log(A)=\log(f(x))+\log(g(x))+\log(h(x))$$ So, taking derivatives $$\frac{1}{A}\frac{dA}{dx}=\frac{f'(x)}{f(x)}+\frac{g'(x)}{g(x)}+\frac{h'(x)}{h(x)}$$
I am sure you can take from here and apply the above to your two problems.
