In our lecture, we are currently learning about electric potential and electric potential energy.
However, I am very confused by the correct use of signs for electric potential.
In the class, we learned that the change in potential difference is equal to $V= -Ed\cos(\theta)$. However, when solving some textbook questions, they somehow seemed to have neglected the negative sign, and just calculated the potential energy/electric field at a point to be positive. i.e. they used the equation $V=Ed\cos(\theta)$ without the negative sign.
Anyone know why??