### 21.2.1 Root mean square

The rms command finds the room mean square of a list of numbers X=[x1,x2,…,xn], which is defined by

RMS(X)=

√

n
∑
k=1

|xk|2

n

.

(See Section 28.2.16 for other uses of rms.)

- rms takes X, a list of real or complex numbers [x1,x2,…,xn].
- rms(X) returns RMS(X) as defined above.

#### Examples

rms([1,2,5,8,3,6,7,9,-1])

√

30

rms([1,1-i,2+3 i,5-2 i])

3
2

√

5