For 5 months i 've had a white coated tongue with a sweet taste in my mouth. what is causing this and how can i get ride of it?

Possibly fungal: See a dentist to confirm the diagnosis but it is likely nothing serious. It may be a mild fungal infection that can be treated with an anti fungal medication, or possibly excess debris that can be reduced with proper oral hygiene. Good luck!

Do not wait: The tongue and the taste combined may be diabetes undiagnosed -------seek medical attention asap.