Recent content by BlackDeath

  1. B

    How to prove that R is equivalence relation

    Got it. thanks :D
  2. B

    How to prove that R is equivalence relation

    Homework Statement let X = {1,2,3,..,10} define a relation R on X x X by (a,b)R(c,d) if ad=bc. show that R is an equivalence relation on X x X. Homework Equations The Attempt at a Solution I think that the R have to be reflexive (because ad=bc). Eg. one of the subset is (1,1)...
  3. B

    One to one and onto in composite function

    Homework Statement I just want to make sure that I am correct. if we have a composite function f(g(x)). Homework Equations f(g(x)) is onto if and only if both f(x) and g(x) are onto f(g(x)) is one to one if and only if or both f(x) and g(x) are one to one The Attempt at a Solution...