private static FloatingPoint CalculateFunctionAtDerivative(
this Expr symbolicExpression,
Dictionary <string, FloatingPoint> variables,
Expr variableForDerivative,
int derivativeDegree)
{
var functionAtDerivative = symbolicExpression.GetDerivativeOfDegree(variableForDerivative, derivativeDegree);
return(functionAtDerivative.Evaluate(variables));
}