PHP Math

Math Function Categories

🔹 Basic Math Functions

PHP's basic math functions handle common operations like absolute values, rounding, and finding minimum/maximum values. These are essential for everyday calculations.

<?php
// Absolute value
echo "abs(-42): " . abs(-42) . "\n";

// Rounding
echo "round(4.7): " . round(4.7) . "\n";
echo "round(4.3): " . round(4.3) . "\n";

// Ceiling (round up)
echo "ceil(4.1): " . ceil(4.1) . "\n";

// Floor (round down)
echo "floor(4.9): " . floor(4.9) . "\n";

// Min and Max
echo "min(2, 5, 1, 8): " . min(2, 5, 1, 8) . "\n";
echo "max(2, 5, 1, 8): " . max(2, 5, 1, 8);
?>

🔹 Power and Root Functions

Calculate powers, square roots, and cube roots with PHP's exponential functions. These are useful for scientific calculations and geometric formulas.

<?php
// Power (base, exponent)
echo "pow(2, 3): " . pow(2, 3) . "\n";
echo "pow(5, 2): " . pow(5, 2) . "\n";

// Square root
echo "sqrt(16): " . sqrt(16) . "\n";
echo "sqrt(25): " . sqrt(25) . "\n";

// Cube root (using pow)
echo "Cube root of 27: " . pow(27, 1/3) . "\n";

// Exponential (e^x)
echo "exp(1): " . round(exp(1), 2) . "\n";

// Natural logarithm
echo "log(10): " . round(log(10), 2);
?>

🔹 Random Number Generation

Generate random numbers for games, simulations, and security. Use random_int() for cryptographically secure random numbers, or rand() for general purposes.

<?php
// Basic random number (0 to max)
echo "rand(): " . rand() . "\n\n";

// Random in range
echo "rand(1, 10): " . rand(1, 10) . "\n";
echo "rand(1, 10): " . rand(1, 10) . "\n\n";

// Better random (Mersenne Twister)
echo "mt_rand(1, 100): " . mt_rand(1, 100) . "\n\n";

// Cryptographically secure random
echo "random_int(1, 6): " . random_int(1, 6) . "\n";

// Random float between 0 and 1
echo "Random float: " . (mt_rand() / mt_getrandmax());
?>

🔹 Rounding with Precision

Control decimal precision when rounding numbers. Specify how many decimal places to keep, or round to the nearest multiple of a number.

<?php
$number = 3.14159;

// Round to different decimal places
echo "Original: $number\n";
echo "round($number, 0): " . round($number, 0) . "\n";
echo "round($number, 2): " . round($number, 2) . "\n";
echo "round($number, 4): " . round($number, 4) . "\n\n";

// Round to nearest 5
$price = 47;
echo "Round $price to nearest 5: " . (round($price / 5) * 5) . "\n";

// Round to nearest 10
echo "Round $price to nearest 10: " . (round($price / 10) * 10);
?>

🔹 Trigonometric Functions

PHP includes all standard trigonometric functions for working with angles. Remember that PHP uses radians, not degrees, so convert when necessary.

<?php
// Convert degrees to radians
$degrees = 45;
$radians = deg2rad($degrees);

echo "Angle: $degrees degrees\n\n";

// Trigonometric functions
echo "sin($degrees°): " . round(sin($radians), 2) . "\n";
echo "cos($degrees°): " . round(cos($radians), 2) . "\n";
echo "tan($degrees°): " . round(tan($radians), 2) . "\n\n";

// Inverse functions
echo "asin(0.5): " . round(rad2deg(asin(0.5)), 2) . "°\n";
echo "acos(0.5): " . round(rad2deg(acos(0.5)), 2) . "°\n";

// Pi constant
echo "\nPI: " . M_PI;
?>

🔹 Number Formatting

Format numbers for display with thousands separators and decimal places. This makes large numbers more readable and ensures consistent decimal precision.

<?php
$number = 1234567.89;

// Format with 2 decimals
echo "number_format($number, 2): " . number_format($number, 2) . "\n\n";

// Custom separators (decimals, decimal_sep, thousands_sep)
echo "US format: " . number_format($number, 2, '.', ',') . "\n";
echo "EU format: " . number_format($number, 2, ',', '.') . "\n\n";

// Currency formatting
$price = 1999.99;
echo "Price: $" . number_format($price, 2) . "\n";

// Percentage
$percent = 0.1567;
echo "Percentage: " . number_format($percent * 100, 1) . "%";
?>

🔹 Math Constants

PHP provides predefined mathematical constants for common values. These are more accurate than manually typing decimal approximations.

<?php
// Pi
echo "M_PI: " . M_PI . "\n";

// Euler's number
echo "M_E: " . M_E . "\n";

// Square root of 2
echo "M_SQRT2: " . M_SQRT2 . "\n";

// Natural log of 2
echo "M_LN2: " . M_LN2 . "\n";

// Log base 10 of E
echo "M_LOG10E: " . M_LOG10E . "\n\n";

// Calculate circle area
$radius = 5;
$area = M_PI * pow($radius, 2);
echo "Circle area (r=$radius): " . round($area, 2);
?>

🔹 Practical Math Examples

Real-world applications of PHP math functions in common programming scenarios like calculating percentages, averages, and distances.

<?php
// Calculate percentage
function percentage($part, $total) {
    return round(($part / $total) * 100, 1);
}
echo "75 out of 200: " . percentage(75, 200) . "%\n\n";

// Calculate average
$scores = [85, 92, 78, 95, 88];
$average = array_sum($scores) / count($scores);
echo "Average score: " . round($average, 1) . "\n\n";

// Distance between two points
function distance($x1, $y1, $x2, $y2) {
    return sqrt(pow($x2 - $x1, 2) + pow($y2 - $y1, 2));
}
echo "Distance (0,0) to (3,4): " . distance(0, 0, 3, 4) . "\n\n";

// Compound interest
$principal = 1000;
$rate = 0.05;
$years = 5;
$amount = $principal * pow(1 + $rate, $years);
echo "Investment after $years years: $" . round($amount, 2);
?>