Let f : R R→Z be the closed binary operation defined
by f (a, b) _ _a + b_. (a) Is f commutative? (b) Is f associative?
(c) Does f have an identity element?
by f (a, b) _ _a + b_. (a) Is f commutative? (b) Is f associative?
(c) Does f have an identity element?