# https://www.chilimath.com/lessons/advanced-algebra/cramers-rule-with-two-variables # https://en.wikipedia.org/wiki/Cramer%27s_rule def cramers_rule_2x2(equation1: list[int], equation2: list[int]) -> str: """ Solves the system of linear equation in 2 variables. :param: equation1: list of 3 numbers :param: equation2: list of 3 numbers :return: String of result input format : [a1, b1, d1], [a2, b2, d2] determinant = [[a1, b1], [a2, b2]] determinant_x = [[d1, b1], [d2, b2]] determinant_y = [[a1, d1], [a2, d2]] >>> cramers_rule_2x2([2, 3, 0], [5, 1, 0]) 'Trivial solution. (Consistent system) x = 0 and y = 0' >>> cramers_rule_2x2([0, 4, 50], [2, 0, 26]) 'Non-Trivial Solution (Consistent system) x = 13.0, y = 12.5' >>> cramers_rule_2x2([11, 2, 30], [1, 0, 4]) 'Non-Trivial Solution (Consistent system) x = 4.0, y = -7.0' >>> cramers_rule_2x2([4, 7, 1], [1, 2, 0]) 'Non-Trivial Solution (Consistent system) x = 2.0, y = -1.0' >>> cramers_rule_2x2([1, 2, 3], [2, 4, 6]) Traceback (most recent call last): ... ValueError: Infinite solutions. (Consistent system) >>> cramers_rule_2x2([1, 2, 3], [2, 4, 7]) Traceback (most recent call last): ... ValueError: No solution. (Inconsistent system) >>> cramers_rule_2x2([1, 2, 3], [11, 22]) Traceback (most recent call last): ... ValueError: Please enter a valid equation. >>> cramers_rule_2x2([0, 1, 6], [0, 0, 3]) Traceback (most recent call last): ... ValueError: No solution. (Inconsistent system) >>> cramers_rule_2x2([0, 0, 6], [0, 0, 3]) Traceback (most recent call last): ... ValueError: Both a & b of two equations can't be zero. >>> cramers_rule_2x2([1, 2, 3], [1, 2, 3]) Traceback (most recent call last): ... ValueError: Infinite solutions. (Consistent system) >>> cramers_rule_2x2([0, 4, 50], [0, 3, 99]) Traceback (most recent call last): ... ValueError: No solution. (Inconsistent system) """ # Check if the input is valid if not len(equation1) == len(equation2) == 3: raise ValueError("Please enter a valid equation.") if equation1[0] == equation1[1] == equation2[0] == equation2[1] == 0: raise ValueError("Both a & b of two equations can't be zero.") # Extract the coefficients a1, b1, c1 = equation1 a2, b2, c2 = equation2 # Calculate the determinants of the matrices determinant = a1 * b2 - a2 * b1 determinant_x = c1 * b2 - c2 * b1 determinant_y = a1 * c2 - a2 * c1 # Check if the system of linear equations has a solution (using Cramer's rule) if determinant == 0: if determinant_x == determinant_y == 0: raise ValueError("Infinite solutions. (Consistent system)") else: raise ValueError("No solution. (Inconsistent system)") else: if determinant_x == determinant_y == 0: return "Trivial solution. (Consistent system) x = 0 and y = 0" else: x = determinant_x / determinant y = determinant_y / determinant return f"Non-Trivial Solution (Consistent system) x = {x}, y = {y}"