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If 3x+4y+k=0 represents the equation of tangent at the vertex of the parabola `16x^(2)-24xy^(2)+14x+2y+7=0`, then the value of k is ________ . |
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Answer» Correct Answer - 3 3 Given that equation of tangent at vertex is 3x+4y+k=0. Let the equation of axis be `4x-3y+lamda=0` Therefore, equation of parabola is `(4x-3y+lamda)^(2)=mu(3x+4y+k)` (1) Given equation of parabola is `16x^(2)-24xy+9y^(2)+14x+2y+7=0` (2) Comparing equations (1) and (2), we get `8lamda-3mu=14,-6lamda-4mu=2,lamda^(2)-kmu=7` Solving, we get `lamda=1,mu=-2andk=3`. |
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