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Ch. 10 - Infinite Sequences and Series
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077당신이 사용하는 게 아니라요?교과서 변경
10장, 문제 10.2.30

Repeating Decimals
Express each of the numbers in Exercises 23–30 as the ratio of two integers.
3.1̅4̅2̅8̅5̅7 = 3.142857142857 ...

검증된 단계별 안내
1
Identify the repeating decimal part of the number. Here, the decimal 3.1̅4̅2̅8̅5̅7̅ means the digits 142857 repeat indefinitely after the decimal point.
Let \( x = 3.142857142857... \). Since the repeating block has 6 digits, multiply both sides by \( 10^6 = 1,000,000 \) to shift the decimal point 6 places to the right: \( 10^6 x = 3142857.142857... \).
Subtract the original number \( x \) from this new equation to eliminate the repeating decimal part: \( 10^6 x - x = 3142857.142857... - 3.142857... \).
Simplify the subtraction to get \( (10^6 - 1) x = 3142854 \), which is \( 999999 x = 3142854 \).
Solve for \( x \) by dividing both sides by 999999: \( x = \frac{3142854}{999999} \). This fraction represents the repeating decimal as a ratio of two integers.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Repeating Decimals

A repeating decimal is a decimal number in which a sequence of digits repeats infinitely. For example, 3.142857142857... has the repeating block '142857'. Recognizing the repeating pattern is essential to convert the decimal into a fraction.
추천 영상:
가이드 코스
08:23
Repeated Integration by Parts

Conversion of Repeating Decimals to Fractions

To express a repeating decimal as a ratio of two integers, set the decimal equal to a variable, multiply to shift the decimal point past the repeating block, and subtract to eliminate the repeating part. Solving the resulting equation yields the fraction form.
추천 영상:
가이드 코스
11:26
Partial Fraction Decomposition: Repeated Linear Factors

Properties of Rational Numbers

Rational numbers are numbers that can be expressed as the ratio of two integers. Every repeating decimal corresponds to a rational number, so understanding this property helps in confirming that the decimal can be converted into a fraction.
추천 영상:
가이드 코스
06:21
Properties of Functions