Transformations and Coordinate Geometry
Function transformations change how graphs look on the coordinate plane. When you add a constant to a function, like f(x) + a, the graph shifts vertically - upward for positive values, downward for negative values. For fx+a, the graph moves horizontally - left for positive values, right for negative values.
With af(x), you're stretching the function vertically by factor a, and if a is negative, you're also reflecting it across the x-axis. For f(ax), the function stretches horizontally by a factor of 1/a, with negative values causing reflection across the y-axis.
In coordinate geometry, remember these essential formulas: gradient formula m = y2−y1/x2−x1, line equation y - y₁ = mx−x1, midpoint formula x1+x2/2, y1+y2/2), and distance formula √(y2−y1)2+(x2−x1)2.
Pro tip: For circle equations, remember the standard form x−a² + y−b² = r², where (a,b) is the centre and r is the radius. This makes finding intersection points with lines much easier!
When working with circles, use the equation x² + y² = r² for circles centered at the origin, and x−a² + y−b² = r² for circles with center (a,b). You can expand this to the general form x² + y² - 2ax - 2by + a² + b² - r² = 0 when needed.