Excel 2007 : Finding a Max value with two variables

I am using an Excel spreadsheet, which I didn't create, therefore do not completely understand the formulas that are being used.

However, I need to find the max positive value (G3) while two variables (P1) and (P2) are input. Currently I input each variable one at a time, then look to see if my max value (G3) is still increasing or has started to decrease.

This is very time consuming. Is there some way I could test (P1) and (P2) using values starting at 0.1 to 10.0 to find the max positive value of (G3)?

Any help is greatly appreciated,

Manassasralph