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math help?

Discussion in 'Chit Chat' started by Gin Uh Fur, Mar 27, 2010.

  1. Gin Uh Fur

    Gin Uh Fur Guest

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    Write an equation of the line satisfying the given conditions.


    Intersects the line y = 2 + 3x at infinitely many places
    if someone could EXPLAIN how to do this that be great. you dont have to do it for me. im just sort of lost.
     
  2. ThePug

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    I believe that it wants the same line. You could rewrite it y = 3x + 2 since it's the same equation.
     
  3. Mogget

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    The explanation: assuming you're stuck with linear functions (no variables being raised to a power: eg x squared), there are only two ways a line can intersect another line: at one point along the line, or at every point along the line. The only function that will intersect a line at every point along the line, is that selfsame line.
     
  4. fragomatrick

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    Its easy ! I am an indian ... so math is like supposed to fun for me! Use the straight line formulae and plot it on a graph....... then take out the value of x in terms of y ....and then substitite the value in the above equation to get LHS=RHS!
    that value would determine the infinte values this equation can have .....!
     
  5. L|L

    L|L
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    A sine function would work, I imagine.
     
  6. Mogget

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    A sine curve would have to be infinitely tall or tilted (the first isn't possible, the second is insanely difficult). A tangent function would work, but I'm assuming Gin Uh Fur is limited to first-order polynomials.
     
  7. Owen

    In Loving Memory Full Member

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    I don't imagine the second option would the that difficult. Why not just have an equation like this: y=2+3x+sin(x). That would intersect the line y=2+3x whenever sin(x) equals zero, and if you go on for infinity, it would be equal to zero at infinitely many places (every multiple of pi).

    I don't think that would be a proper intersection, since the second line never deviates from the first line.
     
  8. egnvectr

    egnvectr Guest

    Your question asks for an equation of a line. Try drawing any two different lines in the plane. There are only two possibilities: either they are parallel lines, or they intersect at exactly one point.
    So no other line has more than one intersection with y = 2 + 3x. Therefore, the only line that intersects it infinitely often is itself.
     
  9. Owen

    In Loving Memory Full Member

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    I suppose I should have added some explanation to my post. For those that aren't familiar with a sine function, the graph of it looks like this:
    [​IMG]
    It extends infinitely in both directions along the x-axis, so that means it wavers between 1 and -1. That means that if you add it to your original function, your new function will waver between being above the original function and below the original function, so it will intersect the function infinitely many times. Here's a graph if you want a visual. I put y=2+3x and y=2+3x+sin(10x) on it. The 10 reduces the wavelength of the sine function, making the intersections more noticeable.
     

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  10. Ben

    Ben
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    I do fully agree with Gamer am I, but the maths Jennifer takes isn't really advanced enough to be considering anything other than a simple y = mx + c line. =)

    Also I always think of the sine wave as boobs standing up for some reason.
     
  11. Gin Uh Fur

    Gin Uh Fur Guest

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    thanks guys for all the help :]
     
  12. Mogget

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    You learned it y = mx + c? Interesting. I was taught y = mx + b.
     
  13. Ben

    Ben
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    Yeah, I guess it's the same thing though. We use + c for the constant after integration and jazz as well~.