ok so here's my question

Find the slope of the tangent line to the curve x^y = y^x at the point (2,4)

im not sure exactly how to go about this, what i've tried so far is taking the natural log of both sides so move the exponents

lnx^y=lny^x

ylnx = xlny

and that's where i get stuck. Am I supposed to differentiate both sides then? Because when I did that so that then I could isolate y' i got the following

y' = y(y-xlny)/x(x-ylnx)