Problem 4
Construct a function such that for all positive rational numbers .
Step 1 of 5: Determine f of one
Detailed analysis
Putting x=y=1 gives . Applying the original equation with x=1 and y=f(1), then using this equality, yields .
Putting x=y=1 gives . Applying the original equation with x=1 and y=f(1), then using this equality, yields .