How do you differentiate y=x^lnxy=xlnx?

1 Answer
Apr 18, 2016

y'=2x^(ln(x)-1)ln(x)

Explanation:

Using logarithmic and implicit differentiation, take the natural logarithm of both sides.

ln(y)=ln(x^ln(x))

Simplify the right hand side using the rule: ln(a^b)=b*ln(a)

ln(y)=ln(x)*ln(x)

ln(y)=(ln(x))^2

Take the derivative of both sides. Recall that the chain rule is in effect on both sides.

(y')/y=2ln(x)overbrace(d/dx(ln(x)))^(=1//x)

(y')/y=(2ln(x))/x

Now, multiply both sides by y=x^ln(x) to solve for y'.

y'=(2x^ln(x)ln(x))/x

Note that we can simplify this be writing x^ln(x)/x as x^ln(x)/x^1=x^(ln(x)-1). Thus,

y'=2x^(ln(x)-1)ln(x)