Question 674335
{{{graph(600,600,-2,9,-9,4,log(2,x+1))}}}
i appears there's a vertical asymptote at x = -1.
the following table helps show that.
<pre>
x	y = log(2,x+1)
-2	#NUM!
-1	#NUM!
-0.9999	-16.60964047
-0.9	-3.321928095
-0.8	-2.321928095
-0.7	-1.736965594
-0.6	-1.321928095
-0.5	-1
0	0
1	1
2	1.584962501
3	2
4	2.321928095
5	2.584962501
6	2.807354922
7	3
8	3.169925001
9	3.321928095
</pre>
you cannot take a log of a negative number of or 0.
that is why the first 2 values in the table are invalid.
that is why the graph stops as just to the right of x -1
log (x+1) will be log(0) when x is equal to -1.