If you use Excel 40 hours a week (and those are the weeks you are on vacation), welcome to the MrExcel channel. Home to 2,400 free Excel tutorials. Bill "MrExcel" Jelen is the author of 67 books about ...

If you understand the definition of a mathematical function, a good way to judge it is that any line drawn parallel to the y-axis intersects with the values in the function’s curve only once. The same ...