To trace dependents across worksheets in Excel, follow these steps:

1. Select the cell that contains the dependent formula in Sheet1.
2. Go to the Formulas tab in the ribbon and click on the "Trace Dependents" button under the "Formula Auditing" section.
3. Excel will show an arrow pointing to the cell in Sheet2 that the formula is referencing. Click on the arrow to expand it.
4. If the referenced cell is in a different worksheet, the arrow will lead to an icon that resembles a spreadsheet. Double-click on the icon to go to the referenced worksheet.
5. Once you are in the referenced worksheet, you can use the "Trace Dependents" button again to see any further dependencies.
6. Repeat steps 3-5 for any other dependent cells that are in different worksheets.

Note that if you have a lot of dependent cells across multiple worksheets, it may be helpful to use the "Workbook" option under the "Trace Dependents" button. This will show all the dependent cells in the entire workbook, regardless of which worksheet they are in.