Question

Let f be a function such that
f(x+ f(y)) = f(x) + y;
then f (2013) -​

Answer 1

Answer:

f(x+f(y))=f(x)+y

f(x)+f²(y)=f(x)+y

f²(y)=y

it's possible, when

f²=1

f=1

f(2013)=2013