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Adding Fractions

  1. Sep 10, 2012 #1
    Just stumbled upon something and I've never been taught it before and cannot see why its true... Hoping someone can help

    x/y + y/x = x^2 + y^2/xy

  2. jcsd
  3. Sep 10, 2012 #2
    Do you mean x/y+y/x=(x^2+y^2)/xy
    Because your original equality is false
  4. Sep 10, 2012 #3


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    Clearly you implied (x2+y2)/xy as opposed to x2+(y2/xy) and to see why this is true, do you know how to add fractions such as 1/2+2/3?
  5. Sep 10, 2012 #4
    Yeah I just forgot my brackets... It came when simplifying this trigonometric equation and just changed from the one form to the other and I got so confused so I looked at what happened and came to that equation, yes but I'd only make the denominators 6 and then add the numerators.
  6. Sep 10, 2012 #5


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    6 = 2*3 isn't it? And with any fraction of the form [tex]\frac{x}{y}[/tex] it is also equivalent to [tex]\frac{ax}{ay}[/tex] for any a (assuming the values aren't equal to 0), and the only way you can add fractions is if their denominators are equal.

    So, what did you do to 1/2+2/3 to solve it, and how can you apply that to your original question?
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