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.
Then, in the 19th century, scientists studying the relatively new field of electrical currents discovered that moving charges produce magnetic effects. A current traveling through a loop of wire creates a magnetic field along the axis of the loop. The direction of the field inside the loop can be found by curling the fingers of the right hand in the direction of the current through the loop; the thumb then points in the direction of the magnetic field.