# Numerical Integration Using JavaScript

Ciprian on Tuesday, May 17, 2022 in Methods, Events and Scopes

This is a quick reminder on how to use mathematical functions inside JavaScript.

Instructions

• Use `*` to indicate multiplication: Type `4*x` for 4x;
• Use `^` to indicate powers: Type `4*x^3` for 4×3 and `12*x^-6` for 12x?6.
• Use parentheses to delimit the argument of a function; i.e., type `sin(x)` rather than `sin x`.
• Use parentheses to define the scope of an operation: For example, type `4*x*(x^2+1)^3` for 4x(x2+1)3 or `4^(2*x+1)` for 42x+1 or `(sin(x))^2` for (sin(x))2.
• Do not type `sin^2(x)` for `sin2(x)`, type `(sin(x))^2` instead.
• Do not use brackets `[ ]` or braces `{ }`, use only parentheses to delimit a mathematics expression.
• Functions you may use:

Trig: `sin`, `cos`, `tan`, `cot`, `sec`, `csc`;

Inverse Trig: `asin`, `acos`, `atan`;

Log/exponential: ln (natural log), or use `log`; exp, the natural exponential; Note: You can also enter the natural exponential exp(x) as `e^x` for ex.

Misc: `sqrt`, usage `sqrt(x)` for ?x (or, use exponential notation: `x^(1/2)`).

See each of the mathematical/trigonometry functions above in their JavaScript form below:

``````function multiply(num1, num2) {
// Multiplies two numbers together
return num1 * num2;
}

function power(base, exponent) {
// Calculates the power of a base to an exponent
return Math.pow(base, exponent);
}

function evaluateExpression(expression) {
// Evaluates a mathematical expression as a string
return eval(expression);
}

function square(x) {
// Calculates the square of a number
return Math.pow(x, 2);
}

function sin(x) {
// Calculates the sine of an angle in radians
return Math.sin(x);
}

function cos(x) {
// Calculates the cosine of an angle in radians
return Math.cos(x);
}

function tan(x) {
// Calculates the tangent of an angle in radians
return Math.tan(x);
}

function cot(x) {
// Calculates the cotangent of an angle in radians
return 1 / Math.tan(x);
}

function sec(x) {
// Calculates the secant of an angle in radians
return 1 / Math.cos(x);
}

function csc(x) {
// Calculates the cosecant of an angle in radians
return 1 / Math.sin(x);
}

function asin(x) {
// Calculates the inverse sine of a value in radians
return Math.asin(x);
}

function acos(x) {
// Calculates the inverse cosine of a value in radians
return Math.acos(x);
}

function atan(x) {
// Calculates the inverse tangent of a value in radians
return Math.atan(x);
}

function ln(x) {
// Calculates the natural logarithm of a value
return Math.log(x);
}

function log(x) {
// Calculates the logarithm of a value
return Math.log(x);
}

function exp(x) {
// Calculates the natural exponential of a value
return Math.exp(x);
}

function sqrt(x) {
// Calculates the square root of a value
return Math.sqrt(x);
}``````

## 2 comments on “Numerical Integration Using JavaScript”

1. John says:

Searched for a way of doing Numerical Integration in js, found how to do basic math instead…

1. You are correct. I was never good at maths or trig in school :)

See the updated JavaScript functions in the updated article above.