Chapter 3: Problem 25
The difference of any even integer minus any odd integer is odd.
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Chapter 3: Problem 25
The difference of any even integer minus any odd integer is odd.
These are the key concepts you need to understand to accurately answer the question.
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Prove that \(\log _{5}(2)\) is irrational.
The following "proof" that every integer is rational is incorrect. Find the mistake. "Proof (by contradiction): Suppose not. Suppose every integer is irrational, Then the integer 1 is irrational. But \(1=1 / 1\), which is rational. This is a contradiction. [Hence the supposition is false and the theorem is true.]"
If \(k\) is an integer, what is \(\lceil k\rceil ?\) Why?
Fill in the blanks in the following proof by contraposition that for all integers \(n\), if \(5 X n^{2}\) then \(5 X n\). Proof (by contraposition): [The contrapositive is: For all integers \(n\), if \(5 \mid n\) then \(5\left\lfloor n^{2}\right.\).] Suppose \(n\) is any integer such that \(\frac{(\mathrm{a})}{-}\) [We must show that (b) ] By definition of divisibility, \(n=\) (c) for some integer \(k\). By substitution, \(n^{2}=\frac{(\mathrm{d})}{-5\left(5 k^{2}\right), \text { But } 5 k^{2} \text { is an integer because it }}\) is a product of integers. Hence \(n^{2}=5 \cdot\) (an integer), and so (e) \([\) as was to be shown \(]\).
Assume that \(m\) and \(n\) are particular integers. \(\begin{array}{ll}\text { a. Is } 6 m+8 n \text { even? } & \text { b. Is } 10 m n+7 \text { odd? }\end{array}\) c. If \(m>n>0\), is \(m^{2}-n^{2}\) composite?
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