Question

derivative of lxl?

Answer 1

http://fwd4.me/17pC

Answer 2

thanks a lot.it made me available to find additional information of it?

Answer 3

the key is the definition:\[|x|=\sqrt{x^2}\]using the chain rule we get\[\frac12(x^2)^{-1/2}(2x)=\frac x{(x^2)^{1/2}}={x\over\sqrt {x^2}}\]