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Homework Help: Inequality calculus proof

  1. Oct 19, 2009 #1
    1. The problem statement, all variables and given/known data

    Let 0< r <1. If x>0 or -1 less than or equal x <0. SHOW THAT (1+x) ^ r <1+rx

    2. Relevant equations

    no relevant equations

    3. The attempt at a solution

    I've tried isolating, but I can't relate x to x or r to r. I can't split the equation because I don't know r.
  2. jcsd
  3. Oct 19, 2009 #2


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    Homework Helper

    Try using the binomial theorem to expand (1+x)r and then think about what 0<r<1 and -1≤x<0 really means for your expansion.
  4. Oct 19, 2009 #3
    "If x>0 or -1 less than or equal x <0."--->I think this statement has some problem.
  5. Oct 19, 2009 #4
    No there is no problem, it's X > 0 OR
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