The electric field is related to potential by E=−∇V.
Given: E=Axi^+Byj^ with A=10 V/m² and B=5 V/m²
This means:
∂x∂V=−Ax and ∂y∂V=−By
Integrating:
V(x,y)=−2Ax2−2By2+C=−5x2−25y2+C
Using the boundary condition at (10,20) where V=500 V:
500=−5(100)−25(400)+C
500=−500−1000+C
C=2000 V
At the origin (0,0):
V(0,0)=−5(0)−25(0)+2000=2000 V