Let f(x)f(y) = f(x) +f(y) + f(xy) - 2. If f(2) = 5. Find f(4)

[jaydev]

Let f(x)f(y) = f(x) +f(y) + f(xy) - 2. If f(2) = 5. Find f(4)
Please provide approach and steps to solve. Thanks.

 

[stapel]

Please provide approach and steps to solve.

I'm sorry, but that's still not how this site works. For further information, please re-read the "Read Before Posting" announcement.

Let f(x)f(y) = f(x) +f(y) + f(xy) - 2. If f(2) = 5. Find f(4)

What are your thoughts? What have you tried? You plugged the given value into the given function and... then what?

Please be complete. Thank you!

 

[HallsofIvy]

A rather obvious "hint" is that 4= 2*2! What does that suggest?

 

[Deleted member 4993]

Let f(x)f(y) = f(x) +f(y) + f(xy) - 2. If f(2) = 5. Find f(4)
Please provide approach and steps to solve. Thanks.

I found it!! It is right there.....

 

[jaydev]

I found it!! It is right there.....

Thanks for your response. I actually meant find f(3) for which was not able to get any combination that could lead to an answer. So f(0), f(1), f(1/2), f(4), f(8) etc can be figured out fairly easily. But f(3), not sure...Would be great if you or someone could suggest a way here.

 

[Steven G]

Thanks for your response. I actually meant find f(3) for which was not able to get any combination that could lead to an answer. So f(0), f(1), f(1/2), f(4), f(8) etc can be figured out fairly easily. But f(3), not sure...Would be great if you or someone could suggest a way here.

Maybe try letting x=3 and y equal some value a which you know f(a) for?????

For the record I believe that you were asked to find f(4) AND f(3). After being able to figure out the value of f(4) from a hint you received now you say that you meant f(3).