We compute the first cohomology of the ortosymplectic Lie superalgebra
osp(1∣2) on the (1,1)-dimensional real superspace with
coefficients in the superspace Dλ,ν;μ of bilinear
differential operators acting on weighted densities. This work is the simplest
superization of a result by Bouarroudj [Cohomology of the vector fields Lie
algebras on RP1 acting on bilinear differential operators,
International Journal of Geometric Methods in Modern Physics
(2005), {\bf 2}; N 1, 23-40]