echo $(( exp(1) ))      # e
echo $(( acos(-1) ))    # PI
x=5
echo $(( sqrt(x) ))     # square root
echo $(( log(x) ))      # logarithm base e
echo $(( log2(x) ))     # logarithm base 2
echo $(( log10(x) ))    # logarithm base 10
echo $(( exp(x) ))      # exponential
x=-42
echo $(( abs(x) ))      # absolute value
x=-5.5
echo $(( floor(x) ))    # floor
echo $(( ceil(x) ))     # ceiling
x=10 y=3
echo $(( pow(x,y) ))    # power