perplexus.info :: Just Math : Functional fiesta

Functional fiesta (Posted on 2021-08-12)

Find all functions f:R->R such that for all x,y∈R

f(xy + 1) = f(x+y) + f(x)f(y)

No Solution Yet Submitted by Danish Ahmed Khan

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re: Solution - problem

| Comment 2 of 3 |

(In reply to Solution by FrankM)

From f(0) + f(0)^2 = 0, it is certainly possible that f(0) = 0. But f(0) = -1 also satisfies the relation.

Now how does the f(0) = -1 branch turn out?

Posted by Brian Smith on 2021-08-13 00:09:29

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