ISFORMULA
Definition: ISFORMULA is a function that returns TRUE if a cell contains a formula, and FALSE if it does not.
Syntax: =ISFORMULA(value)
Situation: This formula is appropriate when you need to check if a cell contains a formula.
Example: If you want to check if cell A1 contains a formula, the formula =ISFORMULA(A1) will return TRUE if it contains a formula, and FALSE if it does not.