Video narration
What does sqrt() actually return? If you've used the square-root button on a calculator, you know the basic idea: enter a number, and get back the number that produces it when multiplied by itself. In code, sqrt(n) takes n as input and returns a value r where r times r equals n. This isn't a mysterious transformation. It's finding the number that squares back to the input. For example, sqrt(25) returns 5. Check the result: 5 times 5 equals 25, so 5 is the square root of 25. That's the relationship: input, function, answer-and the answer works backward to recreate the input. Exact syntax depends on the programming language, and negative inputs can behave differently across languages. But here's the answer: sqrt() returns the number that, multiplied by itself, gives the input. sqrt(25) is 5 because 5 times 5 equals 25.