(2x) 2y = 4e 2x-2y 2y$\ell$n2x = $\ell$n4 + 2x $-$ 2y y = ${{x + \ell n2} \over {1 + \ell n2x}}$ y ' = ${{\left( {1 + \ell n2x} \right) - \left( {x + \ell n2} \right){1 \over x}} \over {{{\left( {1 + \ell n2x} \right)}^2}}}$ y '${\left( {1 + \ell n2x} \right)^2} = \left[ {{{x\ell n2x - \ell n2} \over x}} \right]$