Measurement of the form factors in $D \rightarrow K/\pi e^+ \nu_e$

Using a sample of 1.8 million $D \bar{D}$ mesons collected at the $\psi(3770)$ with the CLEO-c detector, we measure absolute branching fractions as a function of $q^2$, the invariant mass of the $e^+ \nu_e$ pair, for $D^0 \rightarrow K^- e^+ \nu_e$, $D^0 \rightarrow \pi^- e^+ \nu_e$, $D^+\rightarrow K_S^0 e^+ \nu_e $ and $D^+ \rightarrow \pi^0 e^+ \nu_e$. We measure the absolute magnitudes of the form factors $f^+_{K}(0)$ and $f^+_{\pi}(0)$. Using unquenched Lattice QCD calculations of the form factor magnitudes we extract the CKM matrix elements $V_{cs}$ and $V_{cd}$.