Add Stationary Points

README.md

@@ -138,3 +138,4 @@ problem, solution = mathgen.genById(0)
 | 104 | Circumference | Circumference of circle with radius 60 | 376.99111843077515 | circumference |
 | 105 | Combine Like terms | 4x^4 + 6x^4 + 9x^1 + 3x^1 + 5x^4 + 10x^3 | 12x^1 + 10x^3 + 15x^4  | combine_like_terms |
 | 105 | Conditional Probability | Someone tested positive for a nasty disease which only 1.34% of population have. Test sensitivity (true positive) is equal to SN= 98.05% whereas test specificity (true negative) SP= 92.32%. What is the probability that this guy really has that disease? | 14.78% | conditional_probability |
+| 106 | Stationary Points | f(x)=x^3-3x | (-1,2),(1,-2) | stationary_points |

mathgenerator/funcs/__init__.py

@@ -111,3 +111,4 @@ from .decimal_to_bcd import *
 from .circumference import *
 from .combine_like_terms import *
 from .conditional_probability import *
+from .stationary_points import *

mathgenerator/funcs/stationary_points.py

@@ -0,0 +1,21 @@
+from .__init__ import *
+import sympy
+
+def stationaryPointsFunc(maxExp=3, maxCoef=10):
+	while True:
+		x = sympy.symbols('x')
+		problem = 0
+		for exp in range(maxExp+1):
+			coefficient = random.randint(0, maxCoef)
+			problem += coefficient*pow(x,exp)
+		solution = sympy.stationary_points(problem, x)
+
+		if len(solution) != 0:
+			solution = ','.join('({},{})'.format(
+					str(p),
+					sympy.sympify(problem.replace(x,p))
+				) for p in solution)
+			problem = 'f(x)=' + str(problem).replace('**', '^')
+			return problem, solution
+
+stationary_points = Generator("Stationary Points", 106, "f(x)=x^3-3x", "(-1,2),(1,-2)", stationaryPointsFunc)