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## mr.luna 4 years ago when you derive for example 5ln(X^2 +2) why isnt product rule used? my buddy here says five is just a multiplier for derivative of lnf(x), why?

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1. victorarana

You can use that rule but it's not necessary.

2. agdgdgdgwngo

where would you apply the product rule here?

3. mr.luna

isnt it 5*lnf(x)

4. agdgdgdgwngo

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5. mr.luna

beats me dude

6. victorarana

You can apply that rule like this: $\frac{d}{dt} 5\times \ln{(x^2+2)}+5\times\frac{d}{dt}\ln{(x^2+2)}$

7. mr.luna

oh! ok. got it. they cansel.

8. agdgdgdgwngo

...

9. victorarana

Usually it's better to use the chain rule when you have a product of two non constant functions.

10. victorarana

If you apply it to a product of a constant and a function you'll be loosing your time, but your result will be correct

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