i need help with Servo motor

i would like to know if there is a servo motor library that rotates the servo motor from 0 to 90 degree and stay like that for few seconds and then rotates the servo motor back from 90 degree to 0 then delays for 12 hours and does the same thing again?

A servo system mainly consists of three basic components - a controlled device, a output sensor, a feedback system.
This is an automatic closed loop control system. Here instead of controlling a device by applying variable input signal, the device is controlled by a feedback signal generated by comparing output signal and reference input signal.

Alqudimi:
i would like to know if there is a servo motor library that rotates the servo motor from 0 to 90 degree and stay like that for few seconds and then rotates the servo motor back from 90 degree to 0 then delays for 12 hours and does the same thing again?

The Servo library will allow you to send commands to the servo to move it to an angle. The program that you want is easy to write and there are examples available in the IDE to show you how to control the servo.

Is the Arduino going to be doing anything else whilst it is waiting fro the time periods to pass ?