2
TWO (2): The rear view mirror and left side driver's mirror. If the vehicle has no rear window, then TWO outside mirrors are required.
Side view mirrors.
All state laws require vehicles to have rear view mirrors (the ones that mount to the interior windshield).
To give a wider angle of view.
The security mirrors.
adjusting your rear view and side mirrors properly Edit: Or Installing large side mirrors
Called side mirrors. Drivers side mirror/passenger side mirror.
The side view mirrors can be heated for removing ice/snow.
Passenger side mirrors were optional. Some were mechanically (not powered) remote controlled.
On what?
They use convex mirrors to give a wider view.