The electric potential in a certain region is V = α x2 y 2 + β z2 (x 2 − γ) + δ y3 z , where α = 3 V/m4 , β = 5.4 V/m4 , γ = 5 m2 , and δ = 4.5 V/m4 . What is the y component of the electric field Ey at (1.1 m, −1 m, 4.1 m)? Answer in units of V/m.