x | 1/x |
1 | 1 |
2 | .5 |
5 | .2 |
100 | .01 |
1000 | .001 |
1/2 | 2 |
1/10 | 10 |
1/100 | 100 |
0 | Undefined! |
-1 | -1 |
-1/10 | -10 |
-1/100 | -100 |
-500 | -.002 |
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These are enough values to give several co-ordinates to plot on a graph so
you can see what the function is doing. If I picked just x values
1, 2, 3, 4, 5 then I might not realize that this
function soars off to (positive) infinity as I get closer to zero on the
positive side. The function is very close to zero and negative when I
give it a large negative value of x. There's a vertical asymptote at x=0 - the
value for which the function isn't defined.
Tables of values are pretty good tools for giving you a rough sketch,
but if you don't choose good values of x, you might miss important details,
so it's not a rigourous understanding of the function, but it is a good
technique for getting oriented on a function and for double-checking later.
Hope this helps!
Stephen La Rocque>
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