The Student Room Group
<a https://www.thestudentroom.co.uk/showthread.php?t=7467335'> Year 12s: what will be the first way you research your future options? >>
<a https://www.thestudentroom.co.uk/showthread.php?t=7467335'> Year 12s: what will be the first way you research your future options? >>
<a https://www.thestudentroom.co.uk/showthread.php?t=7467335'> Year 12s: what will be the first way you research your future options? >>

Core 3 Differentiation

How do I differentiate 2ln(x/4)? The answer is 2/x but I am not sure what the steps are to get that answer
(edited 7 years ago)
Original post by Yusufff
How do I differentiate 2ln(x/4)? The answer is x/2 but I am not sure what the steps are to get that answer


dont you mean 2x \displaystyle \frac{2}{x}?

well as a generall rule, ddxln⁡(f(x))=f′(x)f(x) \displaystyle \frac{d}{dx} \ln(f(x)) = \frac{f'(x)}{f(x)} if that helps you any
Reply 2
Avatar for Yusufff
Yusufff
OP
10
Original post by DylanJ42
dont you mean 2x \displaystyle \frac{2}{x}?

well as a generall rule, ddxln⁡(f(x))=f′(x)f(x) \displaystyle \frac{d}{dx} \ln(f(x)) = \frac{f'(x)}{f(x)} if that helps you any


Yeah sorry typo :colondollar: Thanks!
Reply 3
Avatar for Yusufff
Yusufff
OP
10
Original post by DylanJ42
dont you mean 2x \displaystyle \frac{2}{x}?

well as a generall rule, ddxln⁡(f(x))=f′(x)f(x) \displaystyle \frac{d}{dx} \ln(f(x)) = \frac{f'(x)}{f(x)} if that helps you any


I have another problem, probably a silly mistake but:
ImageUploadedByStudent Room1475521448.900246.jpg
How did the answer get a 1 on the numerator?


Posted from TSR Mobile
Reply 4
Avatar for trythis
trythis
11
What is dydx,y=x−12 \frac{dy}{dx}, y = \frac{x-1}{2}? That's where you're going wrong.
Reply 5
Avatar for Yusufff
Yusufff
OP
10
Original post by trythis
What is dydx,y=x−12 \frac{dy}{dx}, y = \frac{x-1}{2}? That's where you're going wrong.


y=x−12,dydx=1−12=02 y = \frac{x-1}{2}, \frac{dy}{dx} = \frac{1-1}{2} = \frac{0}{2}

This is what I'm getting, I can't spot the silly mistake o-o
y=12x−12y = \frac {1}{2}x - \frac{1}{2}

Try differentiating that, remembering that differentiating a constant gives you zero
Reply 7
Avatar for Yusufff
Yusufff
OP
10
Original post by drinktheoceans
y=12x−12y = \frac {1}{2}x - \frac{1}{2}

Try differentiating that, remembering that differentiating a constant gives you zero


That just leaves you with 1/2 right? ...Aaand that's what I was doing wrong:facepalm: TY!

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you