$\lim_{x\to a}\left(\frac{\ln\left(x-a\right)}{\ln\left(e^x-e^a\right)}\right)$

$\left[\left(-4\right)^{\left(0\right)}\right]^{\left(5\right)}$

$4\sin^2x\left(\cos\left(x\right)\right)=\cos\left(x\right)$

$\lim_{x\to0}\left(x^2+1\right)\cdot\lim_{x\to0}\left(e^x\right)$

$z^{x+1xz-z^{x}}$

$4t^2+9t^4$