### 2.25.16 Number of zeros in [a,b[ : `sturmab`

`sturmab` takes four arguments: a polynomial expression P, a variable name and two real or complex numbers a and b

- if a and b are reals, `sturmab` returns the number of sign changes of P on ]a; b]. In other words, it returns the number of zeros in [a,b[ of the polynomial P/G where G=gcd(P,diff(P)).
- if a or b are complex, `sturmab` returns the number of complex roots of P in the rectangle having a and b as opposite vertices.

Input :

`sturmab(x```^```2*(x```^```3+2),x,-2,0)`

Output :

`1`

Input :

`sturmab(x```^```3-1,x,-2-i,5+3i`

Output :

`3`

Input :

`sturmab(x```^```3-1,x,-i,5+3i`

Output :

`1`

Warning !!!!
P is defined by its symbolic expression.
Input :
`sturmab([1,0,0,2,0,0],x,-2,0)`,
Output :
`Bad argument type`.