How To Graph Logarithmic Functions?

Identify the parent function (y=log_b(x))

Determine the base (b)

Find the vertical asymptote

Set the argument equal to zero to locate the asymptote

Determine the domain from the argument of the logarithm

Find the range, which is all real numbers

Plot the vertical asymptote as a dashed line

Choose easy x-values that make the logarithm simple

Compute corresponding y-values for those x-values

Plot key points such as ((1,0)), ((b,1)), and ((1/b,-1)) when applicable

Apply horizontal shifts by replacing (x) with (x-h)

Apply vertical shifts by adding (k)

Apply reflections if the function is multiplied by a negative

Apply vertical stretches or compressions if the function is multiplied by a constant

Draw the curve approaching the asymptote and passing through the key points

Check that the graph increases for bases greater than 1

Check that the graph decreases for bases between 0 and 1

Verify the graph stays on the correct side of the asymptote

Label the asymptote, intercepts, and key points if needed

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