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							|  |  |  |  | id: 5900f5131000cf542c510025 | 
					
						
							|  |  |  |  | challengeType: 5 | 
					
						
							|  |  |  |  | title: 'Problem 422: Sequence of points on a hyperbola' | 
					
						
							|  |  |  |  | videoUrl: '' | 
					
						
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										 |  |  |  | localeTitle: 问题422:双曲线上的点序列 | 
					
						
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											2018-10-10 18:03:03 -04:00
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							|  |  |  |  | ## Description
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										 |  |  |  | <section id="description"> | 
					
						
							|  |  |  |  | 假设H是由等式12x2 + 7xy-12y2 = 625定义的双曲线。 | 
					
						
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							|  |  |  |  | 接下来,将X定义为点(7,1)。 可以看出X在H中。 | 
					
						
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							|  |  |  |  | 现在,我们将H中的点序列{Pi:i≥1}定义为: | 
					
						
							|  |  |  |  |   P1 =(13,61/4)。 | 
					
						
							|  |  |  |  |   P2 =(-43/6,-4)。 | 
					
						
							|  |  |  |  |   对于i> 2,Pi是H中与Pi-1不同的唯一点,因此线PiPi-1与线Pi-2X平行。 可以证明Pi是定义明确的,并且其坐标始终是有理的。 | 
					
						
							|  |  |  |  | 您得到P3 =(-19/2,-229/24),P4 =(1267/144,-37/12)和P7 =(17194218091/143327232,274748766781/1719926784)。 | 
					
						
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							|  |  |  |  | 用以下格式找到n = 1114的Pn:如果Pn =(a / b,c / d),其中分数是最低项,而分母是正数,则答案是(a + b + c + d)mod 1 000 007。 | 
					
						
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							|  |  |  |  | 对于n = 7,答案应该是:806236837。 | 
					
						
							|  |  |  |  | </section> | 
					
						
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							|  |  |  |  | ## Instructions
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										 |  |  |  | <section id="instructions"> | 
					
						
							|  |  |  |  | </section> | 
					
						
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							|  |  |  |  | ## Tests
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							|  |  |  |  | <section id='tests'> | 
					
						
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							|  |  |  |  | ```yml | 
					
						
							|  |  |  |  | tests: | 
					
						
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										 |  |  |  |   - text: <code>euler422()</code>应该返回92060460。 | 
					
						
							|  |  |  |  |     testString: assert.strictEqual(euler422(), 92060460); | 
					
						
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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 | 
					
						
							|  |  |  |  | function euler422() { | 
					
						
							|  |  |  |  |   // Good luck! | 
					
						
							|  |  |  |  |   return true; | 
					
						
							|  |  |  |  | } | 
					
						
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							|  |  |  |  | euler422(); | 
					
						
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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 | 
					
						
							|  |  |  |  | // solution required | 
					
						
							|  |  |  |  | ``` | 
					
						
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							|  |  |  |  | /section> |