JavaScript

# Calculating the Area of a Shaped Region Using JavaScript’s Integral Method2 min read

When it comes to determining the area of a specific shape, the integral method is a powerful tool. In this web article, we’ll explore a JavaScript example that demonstrates how to leverage this method for area calculation.

JavaScript Code:

Explanation of the Code:

1. HTML Structure:
• `<!DOCTYPE html>` declares the document type and version.
• The `<html>` element wraps the entire HTML content.
• The `<head>` section contains metadata, including character set and the page title.
• The `<body>` section holds the main content of the page.
2. JavaScript Code:
• The `Math.integral` function is defined to calculate the integral of a quadratic equation ax^2 + bx + c over a given range.
• Parameters:
• `a`, `b`, and `c` are coefficients of the quadratic equation.
• `xa` and `xb` define the integral limits.
• `h` determines the number of iterations, influencing the accuracy of the result.
• Inside the function, a loop iterates through the specified range, calculating the value of the quadratic equation at each point and accumulating the area using the integral method.
3. Sample Usage:
• The script then uses the defined `Math.integral` function with a sample input `(1, 4, 2, 10, 50, 100)`.
• The result is displayed using `window.alert`.

This example provides a basic understanding of how to implement the integral method in JavaScript for area calculations, specifically for quadratic equations. Adjust the coefficients and range according to your specific requirements.

### 1 Comment

• tuseroni says:

a very specific integral. might be better to accept them as an array indicating the order, so:
[1,2,3,4,5]=5x^4+4x^3+3x^2+2x+1, then you would build it as:
function integral(input,x)
{
var res=0;
for(var i=0;i<input.length;i++)
{
power=i+1;
res+=((input[i]*Math.pow(x,power))/power);
}
return res;
}

if one of the numbers was subtracted put in a negative so 2x^2-3x+1 would be [1,-3,2]