{
  "index": "1939-A-1",
  "type": "ANA",
  "tag": [
    "ANA",
    "ALG"
  ],
  "difficulty": "",
  "question": "1. Find the length of the curve \\( y^{2}=x^{3} \\) from the origin to the point where the tangent makes an angle of \\( 45^{\\circ} \\) with the \\( x \\)-axis.",
  "solution": "Solution. The arc in the first quadrant is represented by the equation \\( y=x^{3 / 2} \\), and its slope is \\( \\frac{3}{2} x^{1 / 2} \\). The point \\( P\\left(x_{0}, y_{0}\\right) \\) where the tangent makes an angle of \\( 45^{\\circ} \\) is determined from the relation \\( \\frac{3}{2} x_{0}^{1 / 2}=1 \\), whence \\( x_{0}=\\frac{4}{9} \\) The desired length is therefore\n\\[\n\\left.\\int_{0}^{4 / 9} \\sqrt{1+\\frac{9 x}{4}} d x=\\frac{8}{27}\\left(1+\\frac{9 x}{4}\\right)^{3 / 2}\\right]_{0}^{4 / 9}=\\frac{8}{27}(2 \\sqrt{2}-1)\n\\]",
  "vars": [
    "x",
    "y"
  ],
  "params": [
    "x_0",
    "y_0",
    "P"
  ],
  "sci_consts": [],
  "variants": {
    "descriptive_long": {
      "map": {
        "x": "horizontal",
        "y": "vertical",
        "x_0": "horizzero",
        "y_0": "vertzero",
        "P": "pointp"
      },
      "question": "1. Find the length of the curve \\( vertical^{2}=horizontal^{3} \\) from the origin to the point where the tangent makes an angle of \\( 45^{\\circ} \\) with the \\( horizontal \\)-axis.",
      "solution": "Solution. The arc in the first quadrant is represented by the equation \\( vertical=horizontal^{3 / 2} \\), and its slope is \\( \\frac{3}{2} horizontal^{1 / 2} \\). The point \\( pointp\\left(horizzero, vertzero\\right) \\) where the tangent makes an angle of \\( 45^{\\circ} \\) is determined from the relation \\( \\frac{3}{2} horizzero^{1 / 2}=1 \\), whence \\( horizzero=\\frac{4}{9} \\) The desired length is therefore\n\\[\n\\left.\\int_{0}^{4 / 9} \\sqrt{1+\\frac{9 horizontal}{4}} d horizontal=\\frac{8}{27}\\left(1+\\frac{9 horizontal}{4}\\right)^{3 / 2}\\right]_{0}^{4 / 9}=\\frac{8}{27}(2 \\sqrt{2}-1)\n\\]"
    },
    "descriptive_long_confusing": {
      "map": {
        "x": "maplewood",
        "y": "silverlake",
        "x_0": "moonlight",
        "y_0": "starlitsky",
        "P": "ironbridge"
      },
      "question": "1. Find the length of the curve \\( silverlake^{2}=maplewood^{3} \\) from the origin to the point where the tangent makes an angle of \\( 45^{\\circ} \\) with the \\( maplewood \\)-axis.",
      "solution": "Solution. The arc in the first quadrant is represented by the equation \\( silverlake=maplewood^{3 / 2} \\), and its slope is \\( \\frac{3}{2} maplewood^{1 / 2} \\). The point \\( ironbridge\\left(moonlight, starlitsky\\right) \\) where the tangent makes an angle of \\( 45^{\\circ} \\) is determined from the relation \\( \\frac{3}{2} moonlight^{1 / 2}=1 \\), whence \\( moonlight=\\frac{4}{9} \\) The desired length is therefore\n\\[\n\\left.\\int_{0}^{4 / 9} \\sqrt{1+\\frac{9 maplewood}{4}} d maplewood=\\frac{8}{27}\\left(1+\\frac{9 maplewood}{4}\\right)^{3 / 2}\\right]_{0}^{4 / 9}=\\frac{8}{27}(2 \\sqrt{2}-1)\n\\]"
    },
    "descriptive_long_misleading": {
      "map": {
        "x": "verticalaxis",
        "y": "horizontalaxis",
        "x_0": "infinitypoint",
        "y_0": "grounddepth",
        "P": "locationvoid"
      },
      "question": "Problem:\n<<<\n1. Find the length of the curve \\( horizontalaxis^{2}=verticalaxis^{3} \\) from the origin to the point where the tangent makes an angle of \\( 45^{\\circ} \\) with the \\( verticalaxis \\)-axis.\n>>>\n",
      "solution": "Solution:\n<<<\nSolution. The arc in the first quadrant is represented by the equation \\( horizontalaxis=verticalaxis^{3 / 2} \\), and its slope is \\( \\frac{3}{2} verticalaxis^{1 / 2} \\). The point \\( locationvoid\\left(infinitypoint, grounddepth\\right) \\) where the tangent makes an angle of \\( 45^{\\circ} \\) is determined from the relation \\( \\frac{3}{2} infinitypoint^{1 / 2}=1 \\), whence \\( infinitypoint=\\frac{4}{9} \\) The desired length is therefore\n\\[\n\\left.\\int_{0}^{4 / 9} \\sqrt{1+\\frac{9 verticalaxis}{4}} d verticalaxis=\\frac{8}{27}\\left(1+\\frac{9 verticalaxis}{4}\\right)^{3 / 2}\\right]_{0}^{4 / 9}=\\frac{8}{27}(2 \\sqrt{2}-1)\n\\]\n>>>\n"
    },
    "garbled_string": {
      "map": {
        "x": "qzxwvtnp",
        "y": "hjgrksla",
        "x_0": "mldkvepr",
        "y_0": "znxwtqob",
        "P": "vdjhsqkm"
      },
      "question": "1. Find the length of the curve \\( hjgrksla^{2}=qzxwvtnp^{3} \\) from the origin to the point where the tangent makes an angle of \\( 45^{\\circ} \\) with the \\( qzxwvtnp \\)-axis.",
      "solution": "Solution. The arc in the first quadrant is represented by the equation \\( hjgrksla=qzxwvtnp^{3 / 2} \\), and its slope is \\( \\frac{3}{2} qzxwvtnp^{1 / 2} \\). The point \\( vdjhsqkm\\left(mldkvepr, znxwtqob\\right) \\) where the tangent makes an angle of \\( 45^{\\circ} \\) is determined from the relation \\( \\frac{3}{2} mldkvepr^{1 / 2}=1 \\), whence \\( mldkvepr=\\frac{4}{9} \\) The desired length is therefore\n\\[\n\\left.\\int_{0}^{4 / 9} \\sqrt{1+\\frac{9 qzxwvtnp}{4}} d qzxwvtnp=\\frac{8}{27}\\left(1+\\frac{9 qzxwvtnp}{4}\\right)^{3 / 2}\\right]_{0}^{4 / 9}=\\frac{8}{27}(2 \\sqrt{2}-1)\n\\]"
    },
    "kernel_variant": {
      "question": "For the curve y⁴ = 16 x⁶ in the first quadrant, determine the exact length of the segment whose end-points are the two points at which the tangent to the curve forms angles of 30° and 60° with the positive x-axis.",
      "solution": "(≈ 70 words)  \nSince y ≥ 0, solve for y: y = 2x³ᐟ².  \nIts slope is dy/dx = 3√x.  \nA tangent making an angle θ has slope tan θ, so\n\n 3√x₁ = tan 30° = 1/√3 ⇒ x₁ = 1/27,  \n 3√x₂ = tan 60° = √3  ⇒ x₂ = 1/3.\n\nArc-length  \nL = ∫₁⁄₂₇¹⁄₃ √{1 + (3√x)²} dx  \n = ∫₁⁄₂₇¹⁄₃ √{1 + 9x} dx.\n\nSet u = 1 + 9x, du = 9 dx:\n\n L = (1/9)∫₄⁄₃⁴ u½ du  \n  = (1/9)(2/3)u³ᐟ²│₄⁄₃⁴  \n  = (2/27)(8 − 8/(3√3))  \n  = (16/27)(1 − 1/(3√3)) ≈ 0.550.",
      "_replacement_note": {
        "replaced_at": "2025-07-05T22:17:12.057624",
        "reason": "Original kernel variant was too easy compared to the original problem"
      }
    }
  },
  "checked": true,
  "problem_type": "calculation",
  "iteratively_fixed": true
}