It's not correct the golden-ratio is (-1十√5)/2

You must not forget (1+√5)/2 is also another golden ratio

Abstract

We have famous golden ratio in the history of mathematics. But what is the value of golden ratio? We have six kinds of textbook in Japan. The author was astonished by the different two kinds of value of golden ratio. That is to say, one textbook states the golden ratio is (-1+√5)/2, the other five textbooks state (1 +√5)/2. The author asserts that the golden ratio is “(-1 +√5)/2 or (1+√5)/2.”