Hello guys,

resolving the **mission**: https://app.dataquest.io/m/159/finding-extreme-points/6/power-rule

I think it would be nice to perform the examples of the mission by using the previously managed package `Sympy`

. Here it is an example that could be useful for new users.

Code:

```
import sympy
x, y = sympy.symbols('x y')
derivative_one = sympy.diff(x**5, x)
derivative_two = sympy.diff(x**9, x)
slope_one = int(derivative_one.subs(x, 2))
slope_two = int(derivative_one.subs(x, 0))
```

Notice that the `int`

function is provided just for answer checking purposes.

I would like to complete the section with another possible resolution for the **Finding Extreme Values** task using Sympy. The following few lines could be useful to compute critical points and assing them as relative minimum or relative maximum, taking into account:

- When the slope transitions from positive to negative at a point, it can be a maximum value.
- When the slope transitions from negative to positive at a point, it can be a minimum value.

```
import sympy
x = sympy.symbols('x')
derivative = sympy.diff(x**3-x**2, x)
critical_points = sympy.solvers.solve(derivative, x)
h = 0.025
rel_min = list()
rel_max = list()
for point in critical_points:
before_value = derivative.subs(x, point-h)
after_value = derivative.subs(x, point+h)
if before_value < 0 and after_value > 0:
rel_min.append(point)
elif before_value > 0 and after_value < 0:
rel_max.append(point)
```

Greetings and happy learning.