// 5.12.js
// 2024-09-07
// $Id: 5.12.js 1.1 2024/11/02 12:03:34 s Exp $
//
// df : discount factor
// d : dividend
// r : interest rate
// g : growth rate
// v : value of the company

'use strict'

// function
const sum = (x, y) => x + y;

// input
const n  = 5;
const r  = 0.15;
const g1 = 0.10; // for the next 5 years
const g2 = 0.05; // thereafter
const d0 = 10000;
let i = [];
for(let j = 0; j < n; j++){
    i[j] = j;
};

// calculating
const d1 = d0 * (1 + g1);
const df =  i.map((_, j) => 1 / (1 + r) ** (j + 1));
const v5 = df.map((_, j) => d1 * ((1 + g1) ** j) * df[j]).reduce(sum);
const d5 = d1 * (1 + g1) ** 4;
const v6 = (1 + g2) * d5 / (r - g2) / (1 + r) ** 5;
const v0 = v5 + v6;

// output
console.log('5.12.js');
console.log("r",   r);
console.log("g1", g1);
console.log("g2", g2);
console.log("d0", d0);
console.log("d1", d1);
console.log("df");
df.forEach((x,i) => console.log(i, x.toFixed(3)));
console.log("v5", v5.toFixed(0));
console.log("d5", d5.toFixed(0));
console.log("v6", v6.toFixed(0));
console.log("v0", v0.toFixed(0));
// end