Solving a problem in physics section 11 paragraph 68 el

68. The sphere of radius R has a positive charge, the bulk density of which depends only on the distance r from its center like ρ = ρ0 (1 - r / R), where ρ0 - constant. Assuming that the dielectric constant ε = 1 everywhere, find: a) module of the electric field inside and outside the sphere as a function of r; b) the maximum value of the modulus of Emax and the corresponding value of Rmax.