Power in ℤ/pℤ and in ℤ/pℤ[x] : ^

### 2.31.9 Power in ℤ/pℤ and in ℤ/pℤ[x] : `^`

To compute `a` to the power `n` in ℤ/pℤ, we use the operator `^`. `Xcas` implementation is the binary power algorithm.
Input :

`(5%13)```^```2`

Output :

`-1%13`

To compute `A` to the power `n` in ℤ/pℤ[x], we use the operator `^` and the `normal` command .
Input :

`normal(((2*x+1)%13)```^```5)`

Output :

`(6%13)*x```^```5+(2%13)*x```^```4+(2%13)*x```^```3+(1%13)*x```^```2+(-3%13)*x+1%13`

because 10=−3 (mod 13) 40=1 (mod 13) 80=2 (mod 13) 32=6 (mod 13).