## coolaidd 3 years ago What is the approximate value of the function at x = -3?

1. coolaidd

2. henpen

How high is the line (measured using the y-axis) over the horizontal point (x=) -3?

3. coolaidd

5?

4. CliffSedge

He's saying look above x=-3.

5. henpen

|dw:1347647720757:dw|

6. coolaidd

well up 1 from -3?

7. coolaidd

@henpen ??

8. CliffSedge

It's slightly higher than 1.

9. theEric

Somewhere around there! It looks closest to the y=1 line. To me it looks like 1.2 or somewhere around 1.2, but your teacher may want you to stick to the drawn lines for accuracy. I don't kno! But it is definately about 1. There's no way to konw exactly what it is without knowing how each horizontal value (such as -3) determines the vertical value (like the one we are trying to estimate).

10. theEric

CliffSedge made a good point, saying that it's greater than 1. It's true to say that this mystery value is between 1 and 2.

11. coolaidd

so is there a definite answer i can give?

12. CliffSedge

theEric's guess of 1.2 is pretty good. I really doubt it's higher than 1.3 or 1.4.

13. henpen

The whole point of an approximation is that you DON'T give a definite answer. Guess.

14. theEric

Has your teacher gave you any guidelines for estimating? and thank you!

15. coolaidd

nope :/

16. henpen

Really, I think you're over complicating. It looks sort of like it could be in the vicinity of 1.2 ish. Good enough.

17. coolaidd

thanks guys!

18. CliffSedge

There is a definite (exact) answer to give if you had the equation. You can make a good guess and be definite about how uncertain you are.

19. theEric

Sometimes teachers will want you to estimate a certain way, so that there is only one answer, and that might be the case here. So, in that sense there may be a definate answer where there is no definate value. I'd say just guess about 1.2! That would be what all my teachers would've liked, I think!

20. CliffSedge

It looks like the equation would be $y=\frac{-1}{(x-3)}+1$ If you want to get it exactly.

21. CliffSedge

One of the important things about estimation is that you don't want to claim more precision than you actually have. In this situation, with that scale, you can't really get any better than to estimate to ±½ or ±¼ at best. You can definitely do better than rounding to the nearest whole number, so go out to the tenths place and you'll be fine.

22. theEric

CliffSedge proposed an equation that seems right! Notably, the asemptote is at x=2, and his formula yields y=2 at x=2 which looks pretty exact in the picture.

23. theEric