[ { "prompt": "Distance Formula", "answer": "The distance d between two points (x1, y1) and (x2, y2) is given by d = sqrt((x2 - x1)^2 + (y2 - y1)^2). Example: Find the distance between (1, 2) and (4, 6). d = sqrt((4-1)^2 + (6-2)^2) = sqrt(3^2 + 4^2) = sqrt(9 + 16) = sqrt(25) = 5.", "mnemonic": "Think 'Pythagorean theorem' on a coordinate plane.", "rationale": "Crucial for coordinate geometry questions, often appearing in problems involving lengths of segments, perimeters, or properties of geometric figures. Miscalculation of squares or signs is a common error.", "difficulty": "intermediate", "tag": "Geometry" }, { "prompt": "Quadratic Formula", "answer": "For a quadratic equation ax^2 + bx + c = 0, the solutions for x are x = (-b ± sqrt(b^2 - 4ac)) / 2a. Example: Solve 2x^2 + 5x - 3 = 0. Here a=2, b=5, c=-3. x = (-5 ± sqrt(5^2 - 4*2*(-3))) / (2*2) = (-5 ± sqrt(25 + 24)) / 4 = (-5 ± sqrt(49)) / 4 = (-5 ± 7) / 4. So, x = 2/4 = 1/2 or x = -12/4 = -3.", "mnemonic": "Pop Goes the Weasel song: 'x equals negative b, plus or minus the square root, b squared minus 4ac, all over 2a.'", "rationale": "Essential for solving quadratic equations that cannot be easily factored. Frequently tested in both calculator and non-calculator sections. Pay close attention to signs, especially 4ac.", "difficulty": "intermediate", "tag": "Algebra" }, { "prompt": "Slope-Intercept Form", "answer": "The equation of a line is y = mx + b, where m is the slope and b is the y-intercept. Example: A line passes through (0, 3) and has a slope of 2. What is its equation? Since (0, 3) is the y-intercept, b=3. With m=2, the equation is y = 2x + 3.", "mnemonic": null, "rationale": "Fundamental for linear equations. Often used to find the equation of a line, interpret graphs, or determine relationships between parallel and perpendicular lines. Ensure m and b are correctly identified from given information.", "difficulty": "intermediate", "tag": "Algebra" } ]