Square Root
The number that, multiplied by itself, gives the input.
- Inverse of squaring.
- Appears in distance, SD, RMS, L2 norm.
- Negative inputs give complex numbers (rare in ML).
When to use: Euclidean distance, RMSE, Adam denominator, normalization.
Example: Distance (1, 2)→(4, 6): √((4−1)² + (6−2)²) = √25 = 5.