How do you graph #g(x) = log_3(x - 4)#?

1 Answer
Jun 3, 2016

Make a smooth graph that is gently-sloping-down to horizontal through (35/9, -2), (11/3, -1), (5, 0), (7, 1), (13, 2), ( (31, 3),...,(4+3^N, N)... x = 4 ( downwards ) is its vertical asymptote,

Explanation:

The inverse relation for #y = g(x) = log_3 (x-4)# is

#x-4=3^y#.

So, x = 4 + 3^y#.

As #y to -oo, x to 4#. So, x =4 is the vertical asymptote to the graph.

As #x to oo, y to oo, and d/dx(y)=1/(x-4) to 0#.

A short Table for making graph-by-hand, on a rectangular graph paper, is

#(x. y): (35/9, -2), (11/3, -1), (5, 0), (7, 1), (13, 2), (31, 3), ... , (4+3^N, N), ...#