How to analyze time complexity of a code?

All of the following are characteristics that must be contained in any knowledge representation scheme except

What is the primary difference between the header section of a document and the body? a. the body is displayed on the webpage and the header is not. b. the header is displayed on the webpage and the body is not. c. the tag for the body is self-closing, but the tags for the headers must be closed. d. the tag for the header is self closing, but the tag for the body must be closed.

Verify each identity[tex] \frac{csc}{cot \: x \: + \: tan \: x} = cos \: x[/tex]