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# differentiation watch

1. Show that the maximum value of lnx/x3 is 1/3 e-1

I tried the quotient rule which gave me (x2 - lnx(3x2))/x6

​I don't know how to proceed from here can someone help
2. (Original post by bl64)
Show that the maximum value of lnx/x3 is 1/3 e-1

I tried the quotient rule which gave me (x2 - lnx(3x2))/x6

​I don't know how to proceed from here can someone help
What do you usually do to find a maximum it minimum?
3. (Original post by TenOfThem)
What do you usually do to find a maximum it minimum?
make it = 0 and then differentiate again to work out what type of stationary point it is
but i don't know what number makes it =0
4. (Original post by bl64)
make it = 0 and then differentiate again to work out what type of stationary point it is
but i don't know what number makes it =0
Yes, make it 0

For a fraction to equal 0 the numerator must equal 0

I assume that the question stated that x was not zero
5. are mensuration formulae needed to differentiate given in the formulae booklet?
6. (Original post by Samira siddiqua)
are mensuration formulae needed to differentiate given in the formulae booklet?
The quotient rule is given
Some rules for differentiating trig functions are given

What were you looking for in particular

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