The answer is that it depends on where your audience is. In American English, analyzing is the correct form (along with the infinitive analyze). In British English, the word is spelled analyse.
In British English you are free to use either spelling, as neither is considered wrong. But it is important to remain consistent, not just with the spelling of analyze/analyse but in your whole document.
In American English, analyse would be considered a misspelling.
You can ensure you have the correct spelling of analyzing or analysing with the QuillBot Grammar Checker.