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@tomislater
Created March 22, 2014 21:11
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{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"$$f(f(x)) = -x$$\n",
"\n",
"$$g(x) = f(f(x))$$\n",
"$$g(x) = -x$$\n",
"$$g(x) + x = 0$$"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"def f(x):\n",
" if -1 < x < 1:\n",
" return -1. / (2 * x)\n",
" return 1. / (2 * x)"
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 1
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"g = lambda x: f(f(x))"
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 2
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"def poka(g, x):\n",
" print g(x) == -x\n",
" print g(x) + x == 0\n",
" print g(x), x, \"\\n\""
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 3
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"poka(g, -1.0)\n",
"poka(g, 1.0)\n",
"poka(g, 0.3)\n",
"poka(g, -34.32)\n",
"poka(g, -0.5)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"True\n",
"True\n",
"1.0 -1.0 \n",
"\n",
"True\n",
"True\n",
"-1.0 1.0 \n",
"\n",
"True\n",
"True\n",
"-0.3 0.3 \n",
"\n",
"True\n",
"True\n",
"34.32 -34.32 \n",
"\n",
"True\n",
"True\n",
"0.5 -0.5 \n",
"\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"f = lambda x: -1. / (2 * x) if -1 < x < 1 else 1. / (2 * x)"
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 5
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"g = lambda x: f(f(x))"
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 6
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"poka(g, -1.0)\n",
"poka(g, 1.0)\n",
"poka(g, 0.3)\n",
"poka(g, -34.32)\n",
"poka(g, -0.5)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"True\n",
"True\n",
"1.0 -1.0 \n",
"\n",
"True\n",
"True\n",
"-1.0 1.0 \n",
"\n",
"True\n",
"True\n",
"-0.3 0.3 \n",
"\n",
"True\n",
"True\n",
"34.32 -34.32 \n",
"\n",
"True\n",
"True\n",
"0.5 -0.5 \n",
"\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
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