An infinitely long thin thread is charged uniformly with a linear density of 20 µC/m, and a cylindrical surface of radius R = 3 cm coaxial with it is charged uniformly with a surface density of 100 µC/m^2. Using the Ostrogradsky-Gauss theorem, find the dependence E(r) of the electric field strength on the distance r to the thread for regions inside and outside the cylinder and construct a graph.

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