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---
id: 5900f3a51000cf542c50feb8
challengeType: 5
title: 'Problem 57: Square root convergents'
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forumTopicId: 302168
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---
## Description
< section id = 'description' >
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It is possible to show that the square root of two can be expressed as an infinite continued fraction.
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< div style = 'text-align: center;' > $\sqrt 2 =1+ \frac 1 {2+ \frac 1 {2 +\frac 1 {2+ \dots}}}$</ div >
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By expanding this for the first four iterations, we get:
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$1 + \frac 1 2 = \frac 32 = 1.5$
$1 + \frac 1 {2 + \frac 1 2} = \frac 7 5 = 1.4$
$1 + \frac 1 {2 + \frac 1 {2+\frac 1 2}} = \frac {17}{12} = 1.41666 \dots$
$1 + \frac 1 {2 + \frac 1 {2+\frac 1 {2+\frac 1 2}}} = \frac {41}{29} = 1.41379 \dots$
The next three expansions are $\frac {99}{70}$, $\frac {239}{169}$, and $\frac {577}{408}$, but the eighth expansion, $\frac {1393}{985}$, is the first example where the number of digits in the numerator exceeds the number of digits in the denominator.
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In the first one-thousand expansions, how many fractions contain a numerator with more digits than denominator?
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< / section >
## Instructions
< section id = 'instructions' >
< / section >
## Tests
< section id = 'tests' >
```yml
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tests:
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- text: < code > squareRootConvergents()</ code > should return a number.
testString: assert(typeof squareRootConvergents() === 'number');
- text: < code > squareRootConvergents()</ code > should return 153.
testString: assert.strictEqual(squareRootConvergents(), 153);
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```
< / section >
## Challenge Seed
< section id = 'challengeSeed' >
< div id = 'js-seed' >
```js
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function squareRootConvergents() {
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return true;
}
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squareRootConvergents();
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```
< / div >
< / section >
## Solution
< section id = 'solution' >
```js
// solution required
```
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< / section >