## ParthKohli 4 years ago Can we use the ‘maps to’ symbol to show a solution of an equation?

1. ParthKohli

For example,$\rm 3x = 18 \implies x\mapsto6$Will that be the correct notation?

2. ParthKohli

Also check this one:$\rm x^2 = 9\implies x\mapsto(3,-3)$

3. anonymous

$f:x \rightarrow3x$ is that cornened with functions

4. anonymous

The first is OK because it defines x as a constant function.

5. anonymous

The second defines x as a constant function yielding (3,-3) which doesn't make much sense here... perhaps you mean: $x=\pm3\text{ or }x\in\{3,-3\}$

6. anonymous

x is mapped to 3x -18

7. ParthKohli

What does “mapped to” exactly mean?

8. anonymous

we willneed to variables to talk about mapping

9. anonymous

we will need two variables

10. anonymous

mapped is in relation to functions.

11. ParthKohli

Yes, okay, but how can you say that $$\rm x$$ maps to 3 or -3?

12. anonymous

@ParthKohli a map is a relation between sets; $x\mapsto3\text{ is essentially the same as }F(x)=3$

13. anonymous

|dw:1350632977047:dw| f is a function that maps x to y

14. ParthKohli

Yes, that's exactly what I am taught. Was just confirming. :)

15. anonymous

Where y = f(x)....

16. ParthKohli

Well, so how can say write this? x maps to either 3 or -3.

17. ParthKohli

Yes, yes, I know that. :P

18. anonymous

$y^2-9=x$

19. anonymous

So where is your function?

20. anonymous

$x : \mathbb{R}\to{-3,3}$

21. ParthKohli

Here:$\rm x^2 - 9 = 0$

22. anonymous

$x\in\{-3,3\}\text{ or }x=\pm3$

23. ParthKohli

As I said, I need to use the mapping symbol for showing the solution of an equation.

24. ParthKohli

My current question is, how can we use the mapping symbol to show two solutions of an equation?

25. anonymous

That makes virtually no sense. Do you know what the symbol means?

26. anonymous

That is not usual...

27. ParthKohli

Yes, I know what mapping means... ugh. Can we even use the mapping symbol to show two solutions of an equation?

28. anonymous

Not really...

29. anonymous

$x:y \rightarrow \pm \sqrt{9}$

30. anonymous

If you knew what a map was you wouldn't ask a question like that; no, you can't because that's not what it's for. That's like asking "can I use a telescope to write?"

31. ParthKohli

How would you represent that the solutions of equation $$\rm x^2 = 9$$ are $$3$$ and $$-3$$?

32. anonymous

$x=\pm3\text{ or }x\in\{-3,3\}$

33. anonymous

Well, one way is just to write it like u just did...:-)

34. ParthKohli

What will the full mathematical sentence be? @estudier @oldrin.bataku

35. anonymous

x^2 = 9 -> x = plus/minus 3

36. ParthKohli

$\rm x^2 = 9 \implies x=\pm 3$right?

37. anonymous

That's the same, yes...

38. ParthKohli

Thank you both, I'm returning with another question. :P

39. anonymous

$(x^2=9)\implies(x=\pm3)$

40. UnkleRhaukus

use \mapsto to show the related sets , the independent variable (x) and the dependent variable f