Chapter 4: Problem 22
$$ 7+8+9+10+\cdots+600 $$
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These are the key concepts you need to understand to accurately answer the question.
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Chapter 4: Problem 22
$$ 7+8+9+10+\cdots+600 $$
These are the key concepts you need to understand to accurately answer the question.
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For each integer \(n\) with \(n \geq 2\), let \(P(n)\) be the formula $$ \sum_{i=1}^{n-1} i(i+1)=\frac{n(n-1)(n+1)}{3} $$ a. Write \(P(2)\). Is \(P(2)\) true? b. Write \(P(k)\). c. Write \(P(k+1)\). d. In a proof by mathematical induction that the formula holds for all integers \(n \geq 2\), what must be shown in the inductive step?
$$ 3+4+5+6+\cdots+1000 $$
For each positive integer \(n\), let \(P(n)\) be the formula $$ 1^{2}+2^{2}+\cdots+n^{2}=\frac{n(n+1)(2 n+1)}{6} $$ a. Write \(P(1)\). Is \(P(1)\) true? b. Write \(P(k)\). c. Write \(P(k+1)\). d. In a proof by mathematical induction that the formula holds for all integers \(n \geq 1\), what must be shown in the inductive step?
You have two parents, four grandparents, eight greatgrandparents, and so forth. a. If all your ancestors were distinct, what would be the total number of your ancestors for the past 40 generations (counting your parents' generation as number one)? (Hint: Use the formula for the sum of a geometric sequence.) b. Assuming that each generation represents 25 years, how long is 40 generations? c. The total number of people who have ever lived is approximately 10 billion, which equals \(10^{10}\) people. Compare this fact with the answer to part (a). What do you deduce?
Any sum of two or more integers is a result of successive additions of two integers at a time. For instance, here are a few of the ways in which \(a_{1}+a_{2}+a_{3}+a_{4}\) might be computed: \(\left(a_{1}+a_{2}\right)+\left(a_{3}+a_{4}\right)\) or \(\left.\left(\left(a_{1}+a_{2}\right)+a_{3}\right)+a_{4}\right)\) or \(a_{1}+\left(\left(a_{2}+a_{3}\right)+a_{4}\right)\). Use strong mathematical induction to prove that any sum of two or more even integers is even.
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