How to Use PHP's sqrt() Function to Calculate Square Roots

The sqrt() function in PHP calculates the square root of a given number. It accepts a single numeric argument and returns the square root value.

sqrt() Function Usage

Using sqrt() is straightforward: pass the number whose square root you want as the argument. Below is a basic example:

<code>$number = 16;
$result = sqrt($number);
echo "The square root of $number is: $result";</code>

The above code outputs:

<code>The square root of 16 is: 4</code>

In this example, we pass 16 to sqrt() , store the result in $result , and print it with echo .

The sqrt() function can also handle negative numbers, returning a complex number. For instance:

<code>$number = -9;
$result = sqrt($number);
echo "The square root of $number is: $result";</code>

This code outputs:

<code>The square root of -9 is: 3i</code>

Here, passing -9 to sqrt() yields the complex result 3i , which is then printed.

Note that sqrt() accepts only one argument and the argument must be numeric; providing a non‑numeric value will trigger an error, so ensure the input is a valid number before calling the function.

Additionally, sqrt() returns a floating‑point number. If you need an integer result, you can cast the output explicitly:

<code>$number = 25;
$result = (int) sqrt($number);
echo "The square root of $number is: $result";</code>

The above code outputs:

<code>The square root of 25 is: 5</code>

In this case, the floating‑point result from sqrt() is cast to an integer using (int) before printing.

Summary

The sqrt() function is PHP's built‑in way to compute square roots. It takes a single numeric argument and returns a floating‑point result; you can cast it to an integer if needed. Be aware that passing non‑numeric values causes errors, and negative inputs produce complex numbers.

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