How do you differentiate y=12lnxy=12lnx?

1 Answer
Apr 10, 2018

The derivative of 12lnx12lnx is 12/x12x.

Explanation:

Using the fact that the derivative of lnxlnx is 1/x1x:

color(white)=d/dx[12lnx]=ddx[12lnx]

=12*d/dx[lnx]=12ddx[lnx]

=12*1/x=121x

=12/x=12x

Here's a short proof for the derivative of lnxlnx.

We know that d/dx[x]=1ddx[x]=1, that d/dx[e^x]=e^xddx[ex]=ex, also that e^lnx=xelnx=x:

d/dx[x]=1ddx[x]=1

d/dx[e^lnx]=1ddx[elnx]=1

Chain rule:

e^lnx*d/dx[lnx]=1elnxddx[lnx]=1

x*d/dx[lnx]=1xddx[lnx]=1

d/dx[lnx]=1/xddx[lnx]=1x