Please explain step by step. THank you

4. A circular region with a radius of 10 cm is centered on an x - y coordinate system and contains a uniform electric field pointing in the z direction. The electric field depends on time as E = (E. - at2) k, where Eo = 50 - and a = 20 N C.s2. The field is zero outside of the X circular region. What is the induced magnetic field at t = 2 s at the point x = 5 cm, y = 0? Express your answer in unit-vector form