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Consider the equation of circle x^(2)+y^...

Consider the equation of circle `x^(2)+y^(2)-2x-2lambday -8=0` where `lambda` is variable then answer the following:
The given equation represents a family of circles passing through two fixed points. Find the coordinates of the fixed points.

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To solve the problem, we start with the given equation of the circle: \[ x^2 + y^2 - 2x - 2\lambda y - 8 = 0 \] ### Step 1: Rearranging the Equation We can rearrange the equation to isolate the terms involving \(x\) and \(y\): \[ x^2 - 2x + y^2 - 2\lambda y - 8 = 0 \] ### Step 2: Completing the Square Next, we complete the square for the \(x\) and \(y\) terms. For \(x\): \[ x^2 - 2x = (x - 1)^2 - 1 \] For \(y\): \[ y^2 - 2\lambda y = (y - \lambda)^2 - \lambda^2 \] Substituting these back into the equation gives: \[ (x - 1)^2 - 1 + (y - \lambda)^2 - \lambda^2 - 8 = 0 \] ### Step 3: Simplifying the Equation Now, we simplify the equation: \[ (x - 1)^2 + (y - \lambda)^2 - 1 - \lambda^2 - 8 = 0 \] This simplifies to: \[ (x - 1)^2 + (y - \lambda)^2 = \lambda^2 + 9 \] ### Step 4: Identifying the Fixed Points The equation \((x - 1)^2 + (y - \lambda)^2 = \lambda^2 + 9\) represents a family of circles centered at \((1, \lambda)\) with radius \(\sqrt{\lambda^2 + 9}\). To find the fixed points through which all these circles pass, we need to analyze the situation when \(\lambda\) takes specific values. ### Step 5: Finding Fixed Points To find the fixed points, we can set \(\lambda = k\) for some constant \(k\) and analyze the resulting equations. Setting \(\lambda = 0\): \[ (x - 1)^2 + y^2 = 9 \] This circle has a center at \((1, 0)\) and a radius of \(3\). Setting \(\lambda = 3\): \[ (x - 1)^2 + (y - 3)^2 = 18 \] This circle has a center at \((1, 3)\) and a radius of \(3\sqrt{2}\). The two fixed points that all circles pass through can be found by setting \(y\) to specific values (like \(y = 0\) and \(y = 3\)). ### Final Fixed Points The fixed points are: 1. \((1, 0)\) 2. \((1, 3)\) Thus, the coordinates of the fixed points through which the family of circles passes are \((1, 0)\) and \((1, 3)\).
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Knowledge Check

  • The differential equation of the family of circles passing through the fixed points (a,0) and (-a,0) is

    A
    `y_1(y^2-x^2)+2xy+a^2=0`
    B
    `y_1y^2+xy+a^2x^2=0`
    C
    `y_1(y^2-x^2+a^2)+2xy=0`
    D
    `y_1(y^2+x^2)-2xy+a^2=0`
  • The differential equation of the family of circles passing through the fixed points (a, 0) and (-a, 0) is

    A
    `y_1(y^2-x^2)+2xy+a^2=0`
    B
    `y_1y^2+xy+a^2x^2=0`
    C
    `y_1(y^2-x^2+a^2)+2xy=0`
    D
    none of these
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