Two sharp Chernoff type inequalities are obtained for star body in
R2, one of which is an extension of the dual Chernoff-Ou-Pan
inequality, and the other is the reverse Chernoff type inequality. Furthermore,
we establish a generalized dual symmetric mixed Chernoff inequality for two
planar star bodies. As a direct consequence, a new proof of the the dual
symmetric mixed isoperimetric inequality is presented