In Try This 2 you may have found that the parameters a, b, h, and k change the graph of a logarithmic function in the form in the following ways.

Parameter	Transformation	Example
a	There is a vertical stretch by a factor of |a| about the x-axis. When a < 0, there is a reflection in the x-axis.
b	There is a horizontal stretch by a factor of about the y-axis. When b < 0, there is a reflection in the y-axis.
h	There is a horizontal translation of h units left or right. The h-value affects the vertical asymptote.
k	There is a vertical translation of k units up or down.

You may have also noticed in Try This 2 that the parameters h and b affect the domain:

• The h-value translates the domain left or right.
• If the b-value is negative, the graph is reflected in the y-axis, and so the domain is reflected.

The range is unchanged and is all real numbers.