  Let $f$ be a transcendental meromorphic function in the complex plane
$\mathbb{C}$, and $a$ be a nonzero complex number . We give quantitative
estimates for the characteristic function $T(r,f)$ in terms of
$N(r,1/(f^l(f^{(k)})^n-a))$, for integers $k$, $l$, $n$ greater than 1. We
conclude that $f^l(f^{(k)})^n$ assumes every nonzero finite value infinitely
often.

Complex Variables