Some true/false math question *NEED HELP*

Discussion in 'School Work Help' started by aznlitomik3, Apr 30, 2010.

  1. aznlitomik3

    aznlitomik3 Active Member

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    True or False?

    1) The graph of sin^-1(x+1) never touches the y-axis

    2) If f(x) is a function and f(a) = f(b), then a = b

    3) The range of f(x) = 1 is a single point

    4) The domain of f(x) = 1/(x^3+1) is the set of all real number except -1

    5) If a = b then 2^a = 2^b and (1/2)^a = (1/2)^b

    6) Cos(x - (PI/2)) = cos ((PI/2) - x) for all real numbers x

    7) 2^n - 2^n-1 = 2^n-1 whenever n is an integer

    8) log4(x-1)^2 = 2log(x-1) + log 2 whenever x>1


    THANK YOU!!
     
  2. iiimj4everiii

    iiimj4everiii Well-Known Member

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    1) not sure but i think its false
    2) false
    3) true
    4) true
    5) true
    6) false
    7) true
    8) can't do logs >.<
     
  3. xtirpation

    xtirpation Active Member

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    6 is true, because of the property cos y = cos (-y)
    7. I'm assuming there should be brackets, making the statement 2^n - 2^(n-1) = 2^n-1, in that case, it's true
    8. false, UNLESS the logs on the right side of the statement are of base 2
     
  4. Shinnosuki

    Shinnosuki Member

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    wow is school really that lazy now that they make your math questions into true/false? what happen to show your work and doing real calculations -.-
     
  5. DKNY

    DKNY Well-Known Member

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    just wait for a few years, the schools gonna make u write an essay about math rather than solving it.
     
  6. KilaKilaGirl

    KilaKilaGirl Well-Known Member

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    Are you talking about Abstract mathematics? It's a class about doing proves
     
  7. iiimj4everiii

    iiimj4everiii Well-Known Member

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    cosine is an even function so its false. sine is an odd function so it works for sine not cosine

    ps. nvm ur right.
     
  8. atkwai

    atkwai Member

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    3. false
    the range of f(x) = 1, is a set containing 1 element, R = {1}
    unless u consider a set of size 1 a POINT, and for that u have to define your geometry to be so first.
    Point is defined to be an element in a geometrically described set.