... even,respectively. Then prove that the functions f and g ◦ f are one-one but g is not one-one.Solution: By definiton, it is clear that f is indeed one-one and g is not one-one. Butg ◦f(x) = g(f (x)) = g(2x) ... odd.Thenprove that f is one- one. Is f onto?Solution: Let us use the contrapostive argument to prove that f is one-one. Let if possiblef(x) = f(y), for some x, y ∈ N. Using the definition, one sees that ... alphabet(a) with ONLY consonants?(b) with ON LY vowels?(c) with a consonant as the first letter and a vowel as the second letter?(d) if the vowels appear only at odd positions?4. Determine...