# Integral of dot product

1. Oct 26, 2013

### fredrogers3

Hello, I have a quick question about integrals of dot products. We are learning about magnetic flux as the integral of b dot da. However, what circumstances must be present where we can simplify this integral into (b*a) and ignore the integral?

2. Oct 26, 2013

### Simon Bridge

Consider your question in two parts ... you want to know when $$\vec{B}\cdot d\vec{A}=BdA$$ and, at the same time, $$\int_A B.dA = BA$$ ...