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Reads a second degree equation in a string and calculates its root using the Bhaskara formula
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function calculateBhaskara (a, b, c) { | |
if (a === 0) throw(`the coefficient 'a' cannot be 0 in a second degree equation`) | |
const delta = calculateDelta (a, b, c) | |
const solution = [] | |
if (delta < 0) return solution | |
const sqrtDelta = Math.sqrt(delta) | |
solution.push((-b - sqrtDelta) / (2 * a)) | |
if (delta > 0) solution.push((-b + sqrtDelta) / (2 * a)) | |
return solution | |
} | |
calculateBhaskara(1, -4, 3) // [ 1, 3 ] | |
calculateBhaskara(1, -2, 1) // [ 1 ] | |
calculateBhaskara(1, -2, 2) // [ ] | |
calculateBhaskara(0, 1, 1) // 'Uncaught the coefficient 'a' cannot be 0 in a second degree equation' |
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function calculateDelta (a, b, c) { | |
return b**2 - 4 * a * c | |
} |
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const splitEntryes = /(?<!\+|\-|^)\+(?!$)|(?<!\+|\-|^)(?=\-(?!$))/g | |
const matchX = /x/i | |
const matchXSquared = /x{2}|x\*\*2|x\^2|x²/i | |
const matchNeutralOperator = /(\+|\-|^)(?=\D)(?!\+|\-|$|\.)/g | |
const replaceNeutralOperator = '$11' | |
const matchNumbers = /(?<!\*\*|\^)(\/?\-?[\d.]+)/g | |
const fixOperations = entry => | |
entry.startsWith('/') ? 1 / Number(entry.slice(1)) : Number(entry) | |
const reduceValue = (accumulator, currentValue) => | |
accumulator * currentValue | |
function extractCoeficients (sentence) { | |
const entryes = sentence.split(splitEntryes) | |
const coeficients = { a: 0, b: 0, c: 0 } | |
for (let entry of entryes) { | |
const value = entry | |
.replace(matchNeutralOperator, replaceNeutralOperator) | |
.match(matchNumbers) | |
.map(fixOperations) | |
.reduce(reduceValue) | |
let key = null | |
if (entry.match(matchXSquared)) key = 'a' | |
else if (entry.match(matchX)) key = 'b' | |
else key = 'c' | |
coeficients[key] += value | |
} | |
return coeficients | |
} | |
extractCoeficients('x²-x+1') // { a: 1, b: -1, c: 1 } | |
extractCoeficients('x^2+1.5x+3/2') // { a: 1, b: 1.5, c: 1.5 } | |
extractCoeficients('x²+xx+x**2+x^2') // { a: 4, b: 0, c: 0 } |
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