Main methods of functional requirements analysis and specification for a software system

Question

I have a problem regarding the following question :

Name three main methods of functional requirements analysis and specification for a software system.

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Is the answer

• Feasibility Study
• Requirements Gathering & Analysis
• Requirements Specification

Please help me and Thank you in advance!

Answer 1

This is the answer :)

      1.Formal Specification
      2.Use Case Diagrams
      3.Data Flow Diagrams