College Algebra / Unit 1 Alg 041 short lesson, about 20 seconds
The Principal Square Root
Captions available
The idea
The principal square root of a nonnegative number is the nonnegative number that, multiplied by itself, equals it; the radical symbol √ denotes that root.
In practice
√25 = 5. Both 5² and (−5)² equal 25, but the radical points at the nonnegative one.
Where people slip
√25 is 5, never ±5.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
- Nothing. This is a starting point.
Unlocks
- Nothing yet depends on this.
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