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anonymous

  • one year ago

Express the following using inverse notation 1/(5x^3)

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  1. freckles
    • one year ago
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    what do you mean by inverse notation?

  2. imqwerty
    • one year ago
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    do u mean like - 1/x = x^(-1)

  3. freckles
    • one year ago
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    \[y=\frac{1}{5x^3}\] I think you mean to write this maybe and you are looking for inverse function?

  4. freckles
    • one year ago
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    I have no clue what you mean really

  5. anonymous
    • one year ago
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    The problem says "Express the following in inverse notation"

  6. freckles
    • one year ago
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    You can please define that for me.

  7. anonymous
    • one year ago
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    ill take a picture of it

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  8. imqwerty
    • one year ago
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    i think you are talking about multiplicative inverse? u in 6or7th grade?

  9. anonymous
    • one year ago
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    Alright this is it

  10. anonymous
    • one year ago
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    No Ive just been out of school for five years

  11. freckles
    • one year ago
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    \[\frac{1}{a}=a^{-1}\] @imqwerty made a great guess earlier

  12. freckles
    • one year ago
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    oh I don't know why that is called inverse notation in your class you are just writing the expression with negative exponents instead *

  13. imqwerty
    • one year ago
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    yea :D

  14. anonymous
    • one year ago
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    So where is a good place to practice this because I really don't have a clue how you go the answer.

  15. freckles
    • one year ago
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    you see the exponent 3

  16. freckles
    • one year ago
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    on the bottom there?

  17. anonymous
    • one year ago
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    yup

  18. freckles
    • one year ago
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    \[\frac{1}{5x^3}=\frac{1}{5} \frac{1}{x^3}=\frac{1}{5} x^{-3} \text{ use the rule I gave }\]

  19. freckles
    • one year ago
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    bring that little part to the numerator and change the sign of the exponent

  20. anonymous
    • one year ago
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    That makes sense now.

  21. freckles
    • one year ago
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    another example: \[\frac{5}{3(x+1)} \\ \frac{5}{3} \frac{1}{x+1}=\frac{5}{3} \frac{1}{(x+1)^1} \\ =\frac{5}{3}(x+1)^{-1}\]

  22. anonymous
    • one year ago
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    ah I see. This was easier than what I made it seem.

  23. Rushwr
    • one year ago
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    \[\frac{ 1 }{ 5x ^{3} } = y\] \[5y= \frac{ 1 }{ x ^{3} }\]

  24. Rushwr
    • one year ago
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    \[\sqrt[3]{5y} = x\]

  25. imqwerty
    • one year ago
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    hey is it like the minus sign of the exponent is not written or m getting something wrng.....this has happened to me before http://prntscr.com/8bpkrt

  26. Rushwr
    • one year ago
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    I have this link for you if u aren't sure of what you are doing ! https://www.mathsisfun.com/sets/function-inverse.html

  27. anonymous
    • one year ago
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    |dw:1441192519704:dw|

  28. anonymous
    • one year ago
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    Thanks @Rushwr

  29. freckles
    • one year ago
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    @milianbenja088321 I'm pretty certain "express the following using inverse notation" is not universal to mean \[\text{ to write } \frac{1}{a} \text{ as } a^{-1}\] just so you know

  30. freckles
    • one year ago
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    is this an american class?

  31. anonymous
    • one year ago
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    @freckles yeah i figured as much thats why I was looking for a site to practice on.

  32. anonymous
    • one year ago
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    @freckles its an entrance exam

  33. freckles
    • one year ago
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    most of the sites I can find go backwards they want positive exponents instead of negative exponents

  34. freckles
    • one year ago
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    http://www.purplemath.com/modules/exponent2.htm but you can read it from solution to problem and it is the same thing :p

  35. anonymous
    • one year ago
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    @freckles its cool I appreciate all of your help. I will most certainly check the website out at this point anything will help.

  36. freckles
    • one year ago
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    for example in this link: \[(3x)^{-2}=\frac{(3x)^{-2}}{1}=\frac{1}{(3x)^2} \\ \text{ you can read this as } \\ \frac{1}{(3x)^2}=\frac{(3x)^{-2}}{1}=(3x)^{-2}\]

  37. anonymous
    • one year ago
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    Thanks guys! I have to go. have a good day all!

  38. freckles
    • one year ago
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    you too

  39. mathmate
    • one year ago
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    The "inverse" was meant to be the "multiplicative inverse" and not the inverse of a function. It gets confusing when the context is not clear.

  40. freckles
    • one year ago
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    @mathmate wouldn't the multiplicative inverse of \[\frac{1}{5x^3 } \text{ be } 5x^3 \text{ since } \frac{1}{5x^3} \cdot (5x^3)=1\] but they had \[\frac{1}{5}x^{-3}\] so to me the question still makes no sense

  41. freckles
    • one year ago
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    they should have said write with negative exponents

  42. freckles
    • one year ago
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    and I based this on their solutions

  43. mathmate
    • one year ago
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    I do not disagree with the answer (1/5)x^-3 if the question was "Express the following using inverse notation" and not "Find the inverse of the following expression". Yes, I do find the question tricky, if not sneaky! :)

  44. mathmate
    • one year ago
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    Context, context and context! At a particular grade, there is no confusion. Multiplicative inverse is probably the only one they have learned. I have seen questions asking for the inverse to mean negation, i.e. the additive inverse. It's the same as saying (in high school) "when the discriminant is negative, the quadratic equation has no root." It all depends on the context.

  45. freckles
    • one year ago
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    but \[\frac{1}{5}x^{-3} \text{ is \not the multiplicative inverse of } \frac{1}{5x^3}\]

  46. freckles
    • one year ago
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    oh I think I get what you are saying so why wouldn't the answer be: \[(5x^3)^{-1} \text{ instead }\]

  47. mathmate
    • one year ago
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    They are asking to express the expression in inverse notation, not to find the inverse. So the value of the expression should stay the same, just the notation changes. This way we can safely say: 1/(5x^3) = (1/5)x^(-3). "Express the following with negative exponents" is clear for us, but probably does not achieve the purpose getting the students to learn the term "inverse". Just a guess!

  48. freckles
    • one year ago
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    but (5x^3)^(-1) is equivalent to the original expression and to me it is more an inverse notation because it actually obviously contains the multiplicative inverse inside the ( )^(-1)

  49. mathmate
    • one year ago
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    Yes, I agree that (5x^3)^(-1) fits the concept of inverse even better. Some how I have the impression that the question is biased toward teaching the laws of exponents, so there! If I were to correct (manually), I would accept either option.

  50. freckles
    • one year ago
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    I still think the question would have been better phrased to just write with negative exponents. The answers to me our weird for inverse notation.

  51. freckles
    • one year ago
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    are weird*

  52. mathmate
    • one year ago
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    Yes, I agree that "write with negative exponents" would be more suited for the "correct " answer.

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