exp(): The exponent of e

$value = exp(1);
echo $value; // approximately 2.718281828

<?Php
echo exp(3);// Output is 20.085536923188
echo "<br>";
echo exp(-1);// Output is 0.36787944117144
echo "<br>";
echo exp(0);// Output is 1
echo "<br>";
?>

float exp(float $num)

$num is the exponent. The return value is e raised to that power.

Example 1: Continuous compounding

<?php
$principal = 1000;
$rate = 0.08; // 8% continuously compounded rate
$time = 5;
$amount = $principal * exp($rate * $time);
echo round($amount, 2); // 1491.82
?>

Example 2: Exponential Decay

<?php
$initial_amount = 100;
$decay_constant = 0.03;
$time = 10;
$remaining_amount = $initial_amount * exp(-$decay_constant * $time);
echo "Remaining after 10 years: $remaining_amount";
?>

Example 3: Modeling Population Growth

<?php
$initial_population = 1000;
$growth_rate = 0.02;  // 2% annual growth
$years = 8;
$population = $initial_population * exp($growth_rate * $years);
echo "Population after 8 years: $population";
?>

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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