Final answer:
To display nothing if cell B1 is empty or double its value if not, use the formula '=IF(ISBLANK(B1), "", B1*2)' in Excel. This utilizes the IF and ISBLANK functions for the conditional operation.
Step-by-step explanation:
To achieve the desired functionality in Microsoft Excel, you'll need to use an IF function combined with an ISBLANK function. The formula to enter in the cell where you want the result to appear would be:
=IF(ISBLANK(B1), "", B1*2)
This formula checks whether cell B1 is empty. If B1 is empty, the formula displays nothing. Otherwise, it multiplies the value in B1 by 2. This is a basic conditional operation in Excel that allows for data manipulation based on specific criteria.