Which of the following in not a source on income

Description: write function lastfirst() that takes one argument—a list of strings of the format "lastname, firstname" —and returns a list consisting of two lists: (a) a list of all the last names (b) a list of all the first names

Match the following errors with their definitions. a. #name b. #value c. #ref d. 1. when a formula produces output that is too lengthy to fit in the spreadsheet cell 2. when you enter an invalid cell reference in a formula 3. when you type text in cells that accept numeric data 4. when you type in a cell reference that doesn’t exist

How can you make your column headings stand out?