Examples

• The equation x² + y² = 100 is a symmetric equation. It is the equation of the relationship whose Cartesian graph is a circle centred at the origin and whose radius measures 10 units
• Consider the equation y = 0.5x² - 3. The graphical representation of the corresponding function f(x) = 0.5x² - 3 is shown in red in the graph below : Interchanging the two variables produces the equation x = 0.5y² - 3. The corresponding function is [latex]f\left( x\right) =\pm \sqrt {2x+3}[/latex] whose graphical representation, in blue, is shown in the diagram above. Therefore, the equation y= 0.5x² - 3 is not symmetric since the graphs are not identical.