discrete_mathematics_with_applications/chapter_5/test_yourself.md

Test Yourself

Page 296

1. The notation \sum_{k = m}^{n}{a_k} is read "_____."

The summation from k equals m to n of a sub k.

2. The expanded form of \sum_{k = m}^{n}{a_k} is _____.

 a_m + a_{m + 1} + a_{m + 2} + \dots + a_n 

3. The value of a_1 + a_2 + a_3 + \dots + a_n when n = 2 is "_____."

 a_1 + a_2 

4. The notation \prod_{k = m}^{n}{a_k} is read "_____."

The product from k equals m to n of a sub k.

5. If n is a positive integer, then n! = _____.

 n \cdot (n - 1) \dots \cdot 3 \cdot 2 \cdot 1 

6. \sum_{k = m}^{n}{a_k} + c\sum_{k = m}^{n}{b_k} = _____.

 \sum_{k = m}^{n}{a_k + cb_k} 

7. \left(\prod_{k = m}^{n}{a_k}\right)\left(\prod_{k = m}^{n}{b_k}\right) = _____.

 \prod_{k = m}^{n}{a_kb_k} 

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Test Yourself

Page 309

1. Mathematical induction is a method for proving that a property defined for integers n is true for all values of n that are _____.

greater than or equal to some initial value.

2. Let P(n) be a property defined for integers n and consider constructing a proof by mathematical induction for the statement "P(n) is true for all n \geq a."

a. In the basis step one must show _____.

that P(a) is true.

b. In the inductive step one supposes that _____ for a particular but arbitrarily chosen value of an integer k \geq a. This supposition is called the _____. One then has to show that _____.

P(k) is true; inductive hypothesis; P(k + 1) is true.