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Please, friends, Help! A point P moves so that the sum of the squares of the distances to the lines 3 * x-y +4?

= 0 and x +3 * and 7 = 0 is always equal to 2. Find, identify and trace the locus of P.

Thanks!

Update:

x +3 *y and 7 = 0

2 Answers

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  • bpiguy
    Lv 7
    8 years ago
    Favorite Answer

    Looks like your two lines might be 3x - y + 4 = 0 and x + 3y + 7 = 0. These can be rewritten as

    y = 3x + 4 and y = -1/3 (x + 7)

    These two lines are perpendicular because the product of their slopes is -1. The lines intersect at

    3x + 4 = -1/3 (x + 7) ==> 9x + 12 = -x - 7 ==> 10x = -19 ==> x = -1.9

    y = 3 • 1.9 + 4 = 9.7

    So your answer is a circle centered at (-1.9, 9.7) with radius √2. The locus of P is

    (x + 1.9)^2 + (y - 9.7)^2 = 2 (Answer)

  • 8 years ago

    You might want to ask this question also under the categories Homework Help or Mathematics.

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