Find Min Distance b/w Parabolas: 7/(4*root2)

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SUMMARY

The minimum distance between the curves defined by the equations y² - xy - 2x² = 0 and y² = x - 2 is calculated to be 7/(4√2). The first equation can be factored into two linear components, y = -x and y = 2x, simplifying the problem. By graphing these lines, it becomes evident that the line y = -x is closer to the curve y² = x - 2. The solution involves using the slope form of the tangent to a parabola to determine the distance between the two parallel lines.

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  • Ability to graph linear equations and parabolas
  • Familiarity with distance formulas between lines
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Homework Statement


Find the minimum distance between the curves y^2 - xy - 2x^2 = 0 and y^2 = x - 2.
Ans: 7/(4*root2)

Homework Equations

The Attempt at a Solution


It's supposed to be done using concepts from parabolas. I tried using calc but it got convoluted.
 
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erisedk said:

Homework Statement


Find the minimum distance between the curves y^2 - xy - 2x^2 = 0 and y^2 = x - 2.
Ans: 7/(4*root2)

Homework Equations

The Attempt at a Solution


It's supposed to be done using concepts from parabolas. I tried using calc but it got convoluted.

y^2 - xy - 2x^2 splits into two linear factors. That makes it easier since the graph becomes two lines.
 
Ohhh ok. I didn't realize that was a pair of straight lines.
I did it now. Split it into y=-x and y=2x. Drew a rough graph. It's clear from the graph that y=-x is closer. So, using the slope form of tangent to a parabola, I wrote the equation of tangent with the slope -1, and figured out the distance between the two parallel lines, which comes out to be the answer. Thanks :D
 

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