how do i recover my iphone passcode

You don't.

http://support.apple.com/kb/ht1212

If you've forgotten your passcode, there is no way to recover it. Your passcode is locally stored on your device.

You'll need to put the device into recovery mode and restore it. If you changed the passcode recently and have made a backup before you changed it, you could restore that backup. Otherwise, any recent backups will bring the passcode back with them.

Forgot passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support