Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: I can't figure out if this statement is true or false, i said false

  1. Sep 12, 2006 #1
    This chapter is working with negations of Quantified statements.

    True or False. All the occurrrences of the letter u in the title of this book are lower case. Justify your answer.

    I said false, because they arn't being clear when they say "this" If even 1 book doesn't have a lowercase its false. But what is the method you would go about solving this?

    I never took a negation of a non-if then statement. If its if then, its pretty easy:
    ~(Ax, if P(x) then Q(x)) equivlent too Ex such that P(x) and ~Q(x)
    or

    Ax in D, Q(x) equivlent Ex in D such that ~Q(x)

    Note: A should be upside down, and E should be backwards.

    THanks! :biggrin:
     
  2. jcsd
  3. Sep 13, 2006 #2

    HallsofIvy

    User Avatar
    Science Advisor

    If this problem was in a chapter of your textbook, look at the title of your textbook!
     
  4. Sep 13, 2006 #3
    It was, the title of my text book is:

    Susanna S. Epp
    Discrete Mathematics with applications Third Editition

    So is Susanna S. Epp part of the title? I think not, so it has to be false right?
     
  5. Sep 13, 2006 #4

    0rthodontist

    User Avatar
    Science Advisor

    Are all unicorns green? In logic this translates to,
    For all x, if x is a unicorn, x is green.
    or more informally
    If there is a unicorn, it is green.

    There aren't any unicorns, so the antecedent of that implication is false. So all unicorns are green.

    Does this help you?
     
  6. Sep 13, 2006 #5
    yes I believe so! Since the title of the book has no u's (they don't exist, like the unicorn), So All the occurrrences of the letter u in the title of this book are lower case.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook