Bug Fixes

• Solving quadratics with irrational solutions when a > 1 was yielding incorrect results. Fixed in https://github.com/nicolewhite/algebra.js/commit/a84cb43f89facd23fa03e52f8be5109f78fc32e5.
• Coefficients on variables with degree > 1 were being incorrectly raised to said degree. Fixed in https://github.com/nicolewhite/algebra.js/commit/3b492c3dfaa27ba0c5993971859d341fbfe2347b.

Bug Fixes

Expression Simplification

Expression simplification was failing in certain scenarios where there were multiple like-terms. This was fixed in https://github.com/nicolewhite/algebra.js/commit/96b0e467c16f7d8190cb8717749727ffd2319900.

Parser

Negative Numbers

The parser no longer throws when there are negative numbers, e.g.

var eq = algebra.parse("x^2 + 4 = -4");

Adjacent Parentheses

The parser now interprets anything adjacent to a parenthesis as multiplication, e.g.

var exp = algebra.parse("5(x + 2)");
exp.toString(); // 5x + 10

var exp = algebra.parse("(x + 2)(x + 2)");
exp.toString(); // x^2 + 4x + 4

Bug Fixes

Expression.simplify was failing when the expression consisted only of unsimplified constants. Previously, it would only simplify down to two constants:

exp = new Expression("x").add(3); // x + 3

exp = exp.pow(2, false); // xx + 3x + 3x + 3 * 3

exp = exp.eval({x: 2}, false); // 2 * 2 + 3 * 2 + 3 * 2 + 3 * 3

exp = exp.simplify(); // 6 + 19

Now it simplifies down to the single constant:

exp = exp.simplify(); // 25

Bug Fixes

Single-variable equations with an infinite number of solutions were returning undefined when solved. They now return Fraction(1, 1).

var exp = new Expression("x").add(2); // x + 2

var eq = new Equation(exp, exp); // x + 2 = x + 2

var ans = eq.solveFor("x"); // 1

New Features

Parser

You can now build expressions and equations from strings.

var exp = algebra.parse("x^2 + 4 * x + 4");

var eq = algebra.parse("x^2 + 4 * x + 4 = 0");

Expression Simplification

You can now pass a simplify argument to all Expression operations.

var exp = new Expression("x").add(2); // x + 2

exp = exp.multiply(5, false); // 5x + 5 * 2

exp = exp.simplify(); // 5x + 10

exp = exp.add(5, false); // 5x + 10 + 5

exp = exp.divide(5, false); // 5/5x + 10/5 + 5/5

exp = exp.simplify(); // x + 3

exp = exp.pow(2, false); // xx + 3x + 3x + 3 * 3

exp = exp.eval({x: 2}, false); // 2 * 2 + 3 * 2 + 3 * 2 + 3 * 3

Summation

A summation method has been added to the Expression class. It allows you to sum over a range for a specific variable.

var exp = new Expression("x").add("y").add(3); // x + y + 3

var sum = Expression.summation("x", 3, 6); // 4y + 30