A graph can be horizontally or vertically scaled by multiplying each or coordinate of the graph by a constant factor. This can be represented in function form as for a vertical scaling, or for a horizontal scaling.
A graph is vertically compressed if the values for a given value become smaller. If the values become larger, the graph is vertically stretched. Vertical stretches occur when , while compressions occur when . If , the graph is not affected, while if , the graph is reflected across the axis, as well as stretched or compressed.
Similarly, a graph is horizontally compressed if the values decrease for a given value. If they increase, the graph is horizontally stretched. Horizontal scaling, like translations, are the opposite of what is expected. Stretches occur when , while compressions occur when . If , the graph is not affected, while if , the graph is reflected across the axis, as well as stretched or compressed.
