Can an investor depend on Fundamental Analysis only, Technical analysis only or Both - in valuating a Financial Security?

He can depend on Both because the fundamental analysis as the doctor who  sure the security health  if good or bad and overvalued or undervalued

and the technical analysis as the teacher that help you to answer  questions " which market/sector/ stock " and "when entry/exit " to choice best investment performance and achieve best gains  

so i think it must be depend on both because they2 faces to same coin (not2 coins can use one of them without the another) 

Both fundamental and technical analysis.

By definition stock markets are efficient and there price movements depicts both its technical and fundamentals of a particular stock.

Even though the markets are not completely efficient and technical and fundamental analysis to check the whether a security is overvalued or undervalued.