I was wondering if someone here could help me with onto and one-to-one composite functions. I get the meanings of one-to-one and onto, but I'm just finding it hard applying them to composite functions. For instance if A,B and C are sets and f:A-B and g:B-C then if f isn't onto then is gof onto or not? Also, how can you prove this if it is true? I would have said it wouldn't be onto but I'm not sure how to prove this.(adsbygoogle = window.adsbygoogle || []).push({});

Also, if you use the same sets and g is not one-to-one, then is gof one-to-one or not? I would have said that is wouldn't be one-to-one, but I'm doubting that's correct and I'm unsure of how to prove it. Any help would be much appreciated. Thanks.

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

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!

# Onto and one-to-one composite functions

Loading...

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