How To Graph Logs?

Identify the logarithmic function, such as y = log_b(x), y = ln(x), or y = a log_b(x – h) + k

Determine the base b and any transformations

Find the vertical asymptote

For y = log_b(x), the vertical asymptote is x = 0

For y = log_b(x – h), the vertical asymptote is x = h

Plot key points using known log values

For y = log_b(x), use points such as (1, 0), (b, 1), and (1/b, -1)

Apply shifts, stretches, and reflections to the key points if needed

Draw the asymptote as a dashed line

Plot the transformed key points

Sketch a smooth curve through the points

Make the curve approach the asymptote without crossing it

Ensure the graph exists only on the domain where the log input is positive

Determine the domain from the inside of the logarithm

For y = log_b(x), domain is x > 0

For y = log_b(x – h), domain is x > h

Determine the range

For logarithmic functions, the range is all real numbers

Check intercepts if needed

Find the x-intercept by setting y = 0

Find the y-intercept only if the domain includes x = 0

Use a table of values if more points are needed

Verify the graph matches the base and transformations

Label axes and important points clearly

Suggested for You

Trending Today