- #1

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Here's the problem. k(x) = log3 (x+9)

(the number three is the base)

What steps do I have to do in order to graph this problem? Thank you.

- Thread starter Death
- Start date

- #1

- 10

- 0

Here's the problem. k(x) = log3 (x+9)

(the number three is the base)

What steps do I have to do in order to graph this problem? Thank you.

- #2

HallsofIvy

Science Advisor

Homework Helper

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General rule: If you already know the graph of y= f(x) and have a new graph that involves changing x before applying f, that changes the graph horizontally. That is, adding or subtracting a number from x moves the graph. Multiplying or dividing x stretches or shrinks the graph. If you change the value AFTER applying f, that's a change in y and changes the graph vertically.

For example, you know, I presume, that the graph of y= x

The vertex of y= (x-2)

The graph of y= x

The graph of y= log

Adding 9 to x "moves" the graph 9 places to the left. The asymptote y-axis is, of course, x=0. Replacing x by x+ 9 means the asymptote will be where x+9= 0 which is x= -9. Also, any logarithm graph passes through (1,0) because log(1)= 0. x+9= 1 when x= -8 so

log

The graph of y= log

y= log

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