2018-09-30 22:01:58 +00:00
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---
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id: 5900f5071000cf542c510018
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challengeType: 5
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title: 'Problem 410: Circle and tangent line'
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---
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## Description
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<section id='description'>
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Let C be the circle with radius r, x2 + y2 = r2. We choose two points P(a, b) and Q(-a, c) so that the line passing through P and Q is tangent to C.
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For example, the quadruplet (r, a, b, c) = (2, 6, 2, -7) satisfies this property.
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Let F(R, X) be the number of the integer quadruplets (r, a, b, c) with this property, and with 0 < r ≤ R and 0 < a ≤ X.
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We can verify that F(1, 5) = 10, F(2, 10) = 52 and F(10, 100) = 3384.
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Find F(108, 109) + F(109, 108).
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</section>
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## Instructions
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<section id='instructions'>
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</section>
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## Tests
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<section id='tests'>
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```yml
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2018-10-04 13:37:37 +00:00
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tests:
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- text: <code>euler410()</code> should return 799999783589946600.
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2018-10-08 00:01:53 +00:00
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testString: 'assert.strictEqual(euler410(), 799999783589946600, "<code>euler410()</code> should return 799999783589946600.");'
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2018-09-30 22:01:58 +00:00
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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function euler410() {
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// Good luck!
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return true;
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}
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euler410();
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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```
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</section>
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