Generate the answer for a given question. The question requires common knowledge of English. Make sure that the answer is in detail, long, consistent with the context, and requires general knowledge of English. To be less repetitive, please vary your language for each question. Give a proper explanation to answer, and if necessary, provide the definition of various terms. And conclude your answer if it's long. If you have used other resources (e.g., Merriam Webster's.) to answer the question, include citations in your answer. You don't need to paraphrase the context of your resources, but make sure that your answer is consistent and complete.

For example, a man's name is Jeff Smith. My question is: When should I call him 'Jeff'? When should I call him 'Smith'? When should I call him 'Jeff Smith'? in western.
In general US usage, you would use 'Jeff' if you are friends, contemporaries, or Jeff has asked you to use his first name. First names are often used in casual settings. You would use 'Mr. Smith' (or 'Dr. Smith' or other appropriate title) if you are colleagues, younger than Mr. Smith, or in a formal or business setting. You would use 'Smith' in a very casual setting, particularly when playing sports. You would use 'Jeff Smith' when making an introduction, or if you needed to distinguish him from other Jeffs or Smiths, or sometimes when greeting him.

In a few days, I have to do a class presentation project about the 1920s Harlem Renaissance. I want to say that the movement's original name was the 'New Negro Movement,' but I'm not sure if that's okay. I'm white, and I really don't want to offend anybody in my class. Is it all right to say this word in context? Or, should I ignore its original name, and only refer to it as the Harlem Renaissance?.
Is it okay to use the word 'Negro' in a historical context? Yes, absolutely. If that was term used, even in a pejorative sense, in the context of serious research you can always include things that are true and relevant. I'm white, and I really don't want to offend anybody in my class. That is impossible to answer even if the members of this forum were in your class. It is entirely possibly you could offend somebody. Whether or not your report or talk will offend someone should be the least of your concerns if what you are writing or saying is well researched and based on reliable facts. Academic study, even of sensitive social issues, isn't restricted to nationality, gender, religion, or ethnicity.

I've been asked to give lectures on electromagnetism in English, but I encounter many problems trying to express mathematical formulas since they are written and I do not know how to read them. Are there any references which elaborate the formulas and express what should we call any mathematical sign?.

The following references are useful: Pronunciation Guides for Mathematical Notation, Expressions, and Greek Letters (Reference list) Reading Mathematical Expressions (PDF) How can we speak math? (PDF)

