1, the number symbol fai is φ, and the lowercase is φ, which is 2 1 letter of the Greek alphabet. The English pronunciation is phi, the international phonetic symbol /fai/. Represents magnetic flux, angle, lens power and heat flux. φ can be input with special characters of Sogou Pinyin input method.

2. The specific method is as follows: Switch the input method to sogou input method; Place the mouse cursor anywhere in the taskbar of sogou input method, and then click the right mouse button; On the pop-up page, click "Expression &; Symbol "; Then click "Symbol Daquan"; Click Special Symbols/Greece/Latin in turn, and there are 24 symbols with Greek letters in the first and second rows on the right. Click "φ" to enter.