Natural Logarithm Derivative question

[illu45]

Hi all,

I'm a bit puzzled by one of my homework questions. I got an answer, but I have nothing to check it with and I'm not sure that my answer is correct.

The question states that y=ln(ln(ln(x))), and asks for y'. This is what I've done, but it seems a bit too simple to me.

y=ln(ln(ln(x)))
y'=1/[ln(ln(x)]*(d/dx)[(ln(ln(x))]
y'=1/[ln(ln(x)]*1/[ln(x)]*(d/dx)[ln(x)]
y'=1/[ln(ln(x)]*1/[ln(x)]*1/[x]

If someone could tell me if the answer is right or wrong (and preferably why its wrong), that'd be very much appreciated.

Thanks,
illu45

 

[arildno]

It looks right to me.