Originally Posted by

**bee77** let x be any real number besides 0 ...

the rule for injective functions are that set R of real numbers is (-∞ ,∞ ) -> (-1/∞,1/∞)

injective

f(-∞) = f(-1/∞ ) for all Real numbers

Surjective

f(-∞) = f(-1/∞ ) for all real numbers if we sub into the rational number....

I think this is wrong but the concept of trying to prove surjective and injective to be Bijective is there ...

if I invert the function......f (-∞...∞\{0})-> {-1/∞...1/∞\{0}) to

f^-1 {-1/∞...1∞)->f (-∞...∞)

wouldn't that be bijection? any help would be good ...I had a go but I'm pretty sure I'm wrong