{
  "id": 245039,
  "title": "trigonometric ratios",
  "url": "/competitions/google-smartphone-decimeter-challenge/discussion/245039",
  "author_name": "",
  "post_date": "2021-06-09T11:30:27.489699Z",
  "votes": 6,
  "comment_count": 2,
  "views": 0,
  "content": "<p>I know this is a very basic question, but let me ask it.<br>\nHow should I think about the trigonometric ratios in the haversine distance?(e.g. sinA, cosA when A is the length of the side)<br>\nI've only ever seen angles substituted into sine and cosine, so I'm not sure how to handle them.<br>\nI would appreciate it if you could tell me if there is any material that would be easier to understand.| </p>",
  "messages": [
    {
      "id": "1342359",
      "postDate": "06/09/2021 11:30:27",
      "content": "<p>I know this is a very basic question, but let me ask it.<br>\nHow should I think about the trigonometric ratios in the haversine distance?(e.g. sinA, cosA when A is the length of the side)<br>\nI've only ever seen angles substituted into sine and cosine, so I'm not sure how to handle them.<br>\nI would appreciate it if you could tell me if there is any material that would be easier to understand.| </p>",
      "rawMarkdown": "I know this is a very basic question, but let me ask it.\nHow should I think about the trigonometric ratios in the haversine distance?(e.g. sinA, cosA when A is the length of the side)\nI've only ever seen angles substituted into sine and cosine, so I'm not sure how to handle them.\nI would appreciate it if you could tell me if there is any material that would be easier to understand.|",
      "votes": null
    },
    {
      "id": "1346605",
      "postDate": "06/12/2021 14:04:40",
      "content": "<p>When A is the length of the side, the functions are the <a href=\"https://en.wikipedia.org/wiki/Inverse_trigonometric_functions\" target=\"_blank\">inverse trigonometric functions</a> (arcsin, arccos, etc.). <br>\nIf x = arcsin(A), A = sin(x). (A is the length and x is the angle.)😄</p>",
      "rawMarkdown": "When A is the length of the side, the functions are the [inverse trigonometric functions](https://en.wikipedia.org/wiki/Inverse_trigonometric_functions) (arcsin, arccos, etc.). \nIf x = arcsin(A), A = sin(x). (A is the length and x is the angle.)😄",
      "votes": null
    },
    {
      "id": "1347104",
      "postDate": "06/13/2021 01:05:14",
      "content": "<p>Thank you for answering!</p>\n<p>Now I realize the reason why angles substituded into trigonomic ratios.<br>\nThe reason is that angles are on a unit sphere in  the explanation of haversine distance, and these are expressed in radians, so these are equal to the length of the corresponding side.</p>\n<p>I should have explain my question more precisely..</p>",
      "rawMarkdown": "Thank you for answering!\n\nNow I realize the reason why angles substituded into trigonomic ratios.\nThe reason is that angles are on a unit sphere in  the explanation of haversine distance, and these are expressed in radians, so these are equal to the length of the corresponding side.\n\nI should have explain my question more precisely..",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 1346605,
      "author_name": "hiroshisakiyama",
      "author_url": "",
      "post_date": "06/12/2021 14:04:40",
      "content": "<p>When A is the length of the side, the functions are the <a href=\"https://en.wikipedia.org/wiki/Inverse_trigonometric_functions\" target=\"_blank\">inverse trigonometric functions</a> (arcsin, arccos, etc.). <br>\nIf x = arcsin(A), A = sin(x). (A is the length and x is the angle.)😄</p>",
      "votes": null,
      "replies": [
        {
          "id": 1347104,
          "author_name": "makotktjm",
          "author_url": "",
          "post_date": "06/13/2021 01:05:14",
          "content": "<p>Thank you for answering!</p>\n<p>Now I realize the reason why angles substituded into trigonomic ratios.<br>\nThe reason is that angles are on a unit sphere in  the explanation of haversine distance, and these are expressed in radians, so these are equal to the length of the corresponding side.</p>\n<p>I should have explain my question more precisely..</p>",
          "votes": null,
          "replies": []
        }
      ]
    }
  ],
  "raw_markdown_by_id": {
    "1342359": "I know this is a very basic question, but let me ask it.\nHow should I think about the trigonometric ratios in the haversine distance?(e.g. sinA, cosA when A is the length of the side)\nI've only ever seen angles substituted into sine and cosine, so I'm not sure how to handle them.\nI would appreciate it if you could tell me if there is any material that would be easier to understand.|",
    "1346605": "When A is the length of the side, the functions are the [inverse trigonometric functions](https://en.wikipedia.org/wiki/Inverse_trigonometric_functions) (arcsin, arccos, etc.). \nIf x = arcsin(A), A = sin(x). (A is the length and x is the angle.)😄",
    "1347104": "Thank you for answering!\n\nNow I realize the reason why angles substituded into trigonomic ratios.\nThe reason is that angles are on a unit sphere in  the explanation of haversine distance, and these are expressed in radians, so these are equal to the length of the corresponding side.\n\nI should have explain my question more precisely.."
  },
  "source": "meta"
}