Question

differentiate

f(x)=cos(lnx)

Answer 1

-(sinlnx)/x

Answer 2

use chain rule
\[\Large \frac{d}{dx}(\cos(\ln(x))=-\sin(\ln(x))*\frac{d}{dx}(\ln(x))\]
does that help ?

Answer 3

yep, thanks. and i tried using chain rule, kept messing up somewhere