Help differentiation

I don’t get why I can’t do this to differentiate ln3x becaus the answer is actually 1/3x

ln(3x) = ln(3) + ln(x)
so ...

the answer is 1/x. ln(3x) differentiate the whole thing so do, dy/dx of ln3x. that gets you 1/3x. but then you also have to differentiate the inside of the bracket ie, the 3x. dy/dx of 3x is 3. times the two results together so, 1/3x * 3. this gets you 3/3x. which can then get simplified to 1/x. its just applying chain rule

OP

Is my working correct then??

OP

Original post by mqb2766

ln(3x) = ln(3) + ln(x)
so ...

Is my working correct ?

the derivative of ln(3x) is 1/x, for either of the explanations given above.

Universities Forum Helper

Original post by mqb2766

ln(3x) = ln(3) + ln(x)
so ...

How would you differentiate ln(3) + ln(x) to get 1/x?

Original post by toxicgamage56

How would you differentiate ln(3) + ln(x) to get 1/x?

derivative of ln(x) is 1/x and the derivaive of ln(x) + c is again 1/x. c = ln(3) in this case.

Universities Forum Helper

Original post by mqb2766

derivative of ln(x) is 1/x and the derivaive of ln(x) + c is again 1/x. c = ln(3) in this case.

Oh I see, I get it now. Thanks.

OP

Original post by toxicgamage56

Oh I see, I get it now. Thanks.

Do u have ur a level exams this year?

Universities Forum Helper

Original post by Alevelhelp.1

Do u have ur a level exams this year?

Yes

OP

Original post by toxicgamage56

Yes

Same how’s revision going?? R u doin aqa Alevel maths ?

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