sq_01_python_intro/jupyter_book/02_hilfe.ipynb

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"import math"
]
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"cell_type": "markdown",
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"source": [
"# Hilfe\n",
"\n",
"Hilfe kann man sich für Packages oder Funktionen anzeigen lassen:\n",
"\n",
"`help(math)`\n",
"\n",
"`help(math.sin)`"
]
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"text": [
"Help on built-in function sin in module math:\n",
"\n",
"sin(x, /)\n",
" Return the sine of x (measured in radians).\n",
"\n"
]
}
],
"source": [
"help(math.sin)"
]
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"cell_type": "markdown",
"id": "bf381088-a36b-400d-8a8e-9491c85ee637",
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"Das **/** ist kein Parameter sondern eine Info für fortgeschrittene Programmierer ([Details](https://www.python.org/dev/peps/pep-0570/positional-only%20parameters)). Wir ignorieren dies.\n",
"\n",
" `<TAB>` zeigt verfügbare Funktionen an. Probiert:\n",
"\n",
"`math.<TAB>`\n",
"\n",
"`math.c<TAB>`"
]
},
{
"cell_type": "markdown",
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"source": [
"## Aufgabe\n",
"\n",
"❓ Berechne sin und cos von 0°, 90° und 180°!"
]
},
{
"cell_type": "markdown",
"id": "d89f4342-623b-4b6e-be90-e6774c62a65f",
"metadata": {},
"source": [
"## Lösung\n",
"\n",
"War das Ergebnis richtig?\n",
"\n",
"Die Hilfe sagt, dass man den Parameter von `sin`/`cos` in Radians (Bogenmaß) angeben muss. Gegeben waren aber Grad. D.h. wir müssen dies erst umrechnen. Dazu gibt es auch eine Funktion `math.radians()`. Somit wäre die Lösung:"
]
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"1.0"
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"source": [
"math.sin(math.radians(90))"
]
},
{
"cell_type": "markdown",
"id": "89d942ed-7aac-48d7-ba5e-2d1c0e09a2d3",
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"source": [
" Funktionen sind schachtelbar\n",
"\n",
" Ein Programm besteht aus ineinander geschachtelten Funktionsaufrufen."
]
},
{
"cell_type": "code",
"execution_count": 10,
"id": "3197696b-bf76-46b7-99db-67ad482516ca",
"metadata": {},
"outputs": [
{
"data": {
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"1.2246467991473532e-16"
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"source": [
"math.sin(math.radians(180))"
]
},
{
"cell_type": "markdown",
"id": "c5b2d7d1-d7e4-4372-933c-19063452d1dd",
"metadata": {},
"source": [
"Mmh, das sollte 0 sein.\n",
"\n",
" Beim Rechnen mit Kommazahlen ist die Genauigkeit begrenzt."
]
},
{
"cell_type": "markdown",
"id": "0923f3a5-8e2e-4044-a316-598da598f3db",
"metadata": {},
"source": [
"❓ Was wäre, wenn es `math.radians()` nicht geben würde?"
]
}
],
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