If your equation is in vertex form, then the axis of is: x= h in the general vertex form equation y = (x-h)2 + k. If your equation is in standard form, then the formula for the axis of symmetry is: $$ x = \frac {-b}{ 2a} $$ from the general standard form equation $$ y = ax^2 +bx + c $$.
Lesson Summary. All magnetic fields are created by moving charged particles. Stationary charged particles do not generate magnetic fields. An electromagnet is a magnet that relies on an electric current to produce the magnetic field. The simplest electromagnet is simply a wire carrying a current, which generates a magnetic field all around the wire.
The field can be viewed as the combination of an electric field and a magnetic field. The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. The way in which charges and currents interact with the electromagnetic field is described by Maxwell's equations and the Lorentz force law.