# Just want clarification please for some derived function

• Jan 19th 2013, 08:45 AM
duggielanger
Just want clarification please for some derived function
First off is the composite rule same as the chain rule
Second the derivative of each of the function f(x)= e^5x is it f'(x)=5e^5x and
f(x)=cos(7x) is f'(x)=-7sin7x and are they solved by using the composite/chain rule
• Jan 19th 2013, 11:36 AM
HallsofIvy
Re: Just want clarification please for some derived function
I had never seen the phrase "composite rule" but googling it, yes, it another name for the "chain rule"- used in Britain?

And what you have for the derivatives of e^(5x) and cos(7x) are correct.
• Jan 19th 2013, 11:57 AM
hollywood
Re: Just want clarification please for some derived function
I have never heard the term "composite rule", but I imagine it would mean the chain rule. The chain rule is used to differentiate composite functions - where a function is defined in terms of other functions by applying one and then the other - like h(x) = f(g(x)).

Your derivatives are correct, and in both cases they use the chain rule.

- Hollywood

P.S. HallsofIvy - you beat me to the answer!
• Jan 19th 2013, 03:29 PM
Prove It
Re: Just want clarification please for some derived function
While I am much more familiar with the term "chain rule", it makes perfect sense that it might be called the "composition rule", considering that it is used to differentiate compositions of functions...
• Jan 20th 2013, 01:06 AM
duggielanger
Re: Just want clarification please for some derived function
Thank you everyone , yeah we/ you seem to do that quite often, have different term for the same things in maths and science. Of top of my head can't remember as I have a bad hangover .