Hello Members(adsbygoogle = window.adsbygoogle || []).push({});

I am having a little bit of a problem solving this proof for my Discreet math course.

If g and f o g are onto(Surjective), is f onto(Surjective)? Need to prove. I belive that f has to be Onto.

so I have g: A -> B

f: B -> C

Well I understand that a function is onto(Surjective) when it maps to all images. So for g all the elements in A map(hit) element in B.

So f o g: A -> C where every element of C must be map to. I belive that since C is the Image of f that this means that f must be onto(Surjective).

Can someone give me advise on how to prove this? Or even just some advise in general on proofs.

TIA

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Proof Help

**Physics Forums | Science Articles, Homework Help, Discussion**