{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "# число делится и на 3 и 5\n",
    "def summ(N):\n",
    "    summ = 0\n",
    "    i = 1\n",
    "    for i in range(N+1):\n",
    "        if i % 15 == 0 :\n",
    "            summ = i + summ\n",
    "    return summ\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "45\n"
     ]
    }
   ],
   "source": [
    "print(summ(35))\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "33165\n"
     ]
    }
   ],
   "source": [
    "print(summ(1000))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "#Solve a quadratic equation, x**2 + bx + c = 0.\n",
    "def solve_quad(b, c):\n",
    "    D = (b ** 2 - 4 * c)\n",
    "    x1 = (-b + D ** 0.5) / 2\n",
    "    x2 = (-b - D ** 0.5) / 2\n",
    "    return x1, x2\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "for b=4, c=3: (-1.0, -3.0)\n"
     ]
    }
   ],
   "source": [
    "print(\"for b=4, c=3:\", solve_quad(4, 3))\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "for b=2, c=1: (-1.0, -1.0)\n"
     ]
    }
   ],
   "source": [
    "print(\"for b=2, c=1:\", solve_quad(2, 1))\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "for b=0.5, c=4: ((-0.2499999999999999+1.984313483298443j), (-0.2500000000000001-1.984313483298443j))\n"
     ]
    }
   ],
   "source": [
    "print(\"for b=0.5, c=4:\", solve_quad(0.5, 4))\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "for b=1e10, c=3: (0.0, -10000000000.0)\n"
     ]
    }
   ],
   "source": [
    "print(\"for b=1e10, c=3:\", solve_quad(1e10, 3))\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "for b=-1e10, c=3: (10000000000.0, 0.0)\n"
     ]
    }
   ],
   "source": [
    "print(\"for b=-1e10, c=3:\", solve_quad(-1e10, 4))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
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   "display_name": "Python 3",
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