Functions
\(\blacksquare\) A function from set \(X\) to set \(Y\) is a special relation that maps each element \(x\) in set \(X\) to only one element \(y\) in set \(Y\).
Example:
\(\blacksquare\) A function can be written as \(f:x \rightarrow 3x\) or \(f(x)=3x\), where \(x\) is the object and \(3x\) is the image.
\(\blacksquare\) Only one-to-one relation and many-to-one relation are functions.
\(\blacksquare\) When a graph is given, vertical line test can be used to determine whether the graph is a function.
Prepare exams with mock exam papers