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Limits and Boundary and Func help

  1. Oct 12, 2009 #1
    How close to 4 do we have to take x so that 3x + 2 is within a distance of (a) 0.1 and (b) 0.01 from 14?

    http://i.imagehost.org/0222/Picture_1.png [Broken]

    a) Let k be any integer. Prove that if k^3 is even, then k is even.

    b) Prove that 3√2 is irrational. Hint: Mimic the proof that √2 is irrational and apply the result from part (a).

    c) Suppose two numbers a and b are irrational. Must the sum a + b be irrational? Justify your answer with an appropriate proof or counterexample

    Thanks guys!
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Oct 12, 2009 #2


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    These look like homework problems. Are they? What have you tried on them?
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