Math 99 (Notes)
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Final Exam Review Sheet:

For the final exam, it would help you to do the following things:

  1. Learn the definitions you needed to know for the quizzes and for the midterm exam. Know the definitions precisely. You should know the statements in formal language, as well as interpretations in words. E.g., "A is a subset of B" means "("x)(xA xB)" and this can be read as "everything in A is also in B".


  2. Do "blank-paper practice" for the problems on the problem sets and the midterm. Note: You should be able to do all the problems, including the hard ones. Avoid repeating a mistake you made on the problem set (this is important).


  3. Understand these challenging concepts (plus the ones from the midterm):

    1. The definitions of one-to-one and onto.
    2. The image of a set under a function and how xA relates to yf(A).
    3. The inverse image of a set under a function and how yB relates to xf-1(B).
    4. How f-1(f(A)) relates to A and f(f-1(B)) relates to B.
    5. The difference between onto and f(A).
    6. The difference between f-1(B) (the set) and f-1 (the function).
    7. The difference between a|b and b/a.
    8. The fact that x and x2 are not inverses.


  4. In addition to the proofs listed for the midterm, know the proofs of these key examples. You should not memorize them, but should remember the central idea(s) and reconstruct the proof from that memorized core.

    1. if f: X -> Y is one-to-one, then f(AB)=f(A)f(B) for all A,BX (PS5#6)
    2. If f and g are bijections then so is gof (theorem 7.14)
    3. If f and g are bijections then (gof)-1 = f-1og-1 (theorem 7.14)
    4. Af-1(B) iff f(A)B (PS6#1)
    5. n on Z, defined by anb iff n|b-a, is an equivalence relation (PS6#5)


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Created: 04 Nov 2000
Last modified: 04 Nov 2000 10:28:33
Comments to: dpvc@union.edu
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