freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-422-sequence-of-points-on-a-hyperbola.md

---
id: 5900f5131000cf542c510025
title: 'Problem 422: Sequence of points on a hyperbola'
challengeType: 5
forumTopicId: 302092
dashedName: problem-422-sequence-of-points-on-a-hyperbola
---

# --description--

Let $H$ be the hyperbola defined by the equation $12x^2 + 7xy - 12y^2 = 625$.

Next, define $X$ as the point (7, 1). It can be seen that $X$ is in $H$.

Now we define a sequence of points in $H, \\{P_i : i ≥ 1\\}$, as:

- $P_1 = (13, \frac{61}{4})$.
- $P_2 = (\frac{-43}{6}, -4)$.
- For $i > 2$, $P_i$ is the unique point in $H$ that is different from $P_{i - 1}$ and such that line $P_iP_{i - 1}$ is parallel to line $P_{i - 2}X$. It can be shown that $P_i$ is well-defined, and that its coordinates are always rational.

<img class="img-responsive center-block" alt="animation showing defining points P_1 to P_6" src="https://cdn.freecodecamp.org/curriculum/project-euler/sequence-of-points-on-a-hyperbola.gif" style="background-color: white; padding: 10px;">

You are given that $P_3 = (\frac{-19}{2}, \frac{-229}{24})$, $P_4 = (\frac{1267}{144}, \frac{-37}{12})$ and $P_7 = (\frac{17\\,194\\,218\\,091}{143\\,327\\,232}, \frac{274\\,748\\,766\\,781}{1\\,719\\,926\\,784})$.

Find $P_n$ for $n = {11}^{14}$ in the following format: If $P_n = (\frac{a}{b}, \frac{c}{d})$ where the fractions are in lowest terms and the denominators are positive, then the answer is $(a + b + c + d)\bmod 1\\,000\\,000\\,007$.

For $n = 7$, the answer would have been: $806\\,236\\,837$.

# --hints--

`sequenceOfPointsOnHyperbola()` should return `92060460`.

```js
assert.strictEqual(sequenceOfPointsOnHyperbola(), 92060460);
```

# --seed--

## --seed-contents--

```js
function sequenceOfPointsOnHyperbola() {

  return true;
}

sequenceOfPointsOnHyperbola();
```

# --solutions--

```js
// solution required
```