  Symmetry considerations are of extreme importance to the topological
properties of crystals. A crystal field splitting {\delta} yields Dirac nodes
near the Brillouin zone center in Cd3As2, but its value has yet to be
determined with precision. We study the band structure of Cd3As2 using
magnetooptical infrared spectroscopy measurements on epilayers with low carrier
density grown by molecular beam epitaxy. By combining angular dependent
cyclotron resonance with Landau level spectroscopy measurements in the Faraday
geometry, we determine that {\delta} is positive and equal to 15+/-5 meV in
Cd3As2. Our results lead to a more accurate knowledge of the details of the
band structure of this Dirac semimetal such as the position its Dirac nodes in
momentum space and their splitting into Weyl nodes under a magnetic field.
