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The product of the perpendicular drawn from the point `(x_(1),y_(1))` on the lines represented by `ax^(2)+2hxy+by^(2)=0` is ………

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To find the product of the perpendiculars drawn from the point \((x_1, y_1)\) to the lines represented by the equation \(ax^2 + 2hxy + by^2 = 0\), we can follow these steps: ### Step 1: Identify the Lines The given equation \(ax^2 + 2hxy + by^2 = 0\) represents two straight lines. We can express these lines in slope-intercept form as: \[ y = m_1x \quad \text{and} \quad y = m_2x \] where \(m_1\) and \(m_2\) are the slopes of the lines. ### Step 2: Use the Relationships of Roots From the quadratic equation formed by the slopes, we know: - The sum of the roots (slopes) is given by: \[ m_1 + m_2 = -\frac{2h}{b} \] - The product of the roots (slopes) is given by: \[ m_1 m_2 = \frac{a}{b} \] ### Step 3: Calculate the Perpendicular Distances The perpendicular distance \(d\) from the point \((x_1, y_1)\) to the line \(y = mx\) is given by the formula: \[ d = \frac{|y_1 - mx_1|}{\sqrt{1 + m^2}} \] For both lines, the distances will be: \[ d_1 = \frac{|y_1 - m_1x_1|}{\sqrt{1 + m_1^2}} \quad \text{and} \quad d_2 = \frac{|y_1 - m_2x_1|}{\sqrt{1 + m_2^2}} \] ### Step 4: Find the Product of the Distances The product of the perpendicular distances from the point \((x_1, y_1)\) to the two lines is: \[ P = d_1 \cdot d_2 = \left(\frac{|y_1 - m_1x_1|}{\sqrt{1 + m_1^2}}\right) \cdot \left(\frac{|y_1 - m_2x_1|}{\sqrt{1 + m_2^2}}\right) \] ### Step 5: Substitute the Values Substituting the expressions for \(m_1\) and \(m_2\): \[ P = \frac{|y_1 - m_1x_1| \cdot |y_1 - m_2x_1|}{\sqrt{(1 + m_1^2)(1 + m_2^2)}} \] ### Step 6: Simplify the Expression Using the relationships \(m_1 + m_2 = -\frac{2h}{b}\) and \(m_1 m_2 = \frac{a}{b}\), we can simplify the numerator and denominator: 1. The numerator becomes: \[ |y_1^2 - (m_1 + m_2)x_1y_1 + m_1m_2x_1^2| = |y_1^2 + \frac{2h}{b}x_1y_1 + \frac{a}{b}x_1^2| \] 2. The denominator simplifies to: \[ \sqrt{1 + m_1^2 + m_2^2 + m_1^2m_2^2} \] ### Final Result Thus, the product of the perpendiculars drawn from the point \((x_1, y_1)\) to the lines represented by the equation \(ax^2 + 2hxy + by^2 = 0\) is: \[ P = \frac{|b(y_1^2 + \frac{2h}{b}x_1y_1 + \frac{a}{b}x_1^2)|}{\sqrt{(a - b)^2 + 4h^2}} \]
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Knowledge Check

  • The product of perpendiculars let fall from the point (x_(1),y_(1)) upon the lines represented by ax^(2)+2hxy+by^(2) , is

    A
    `(|ax_(1)^(2)+2hx_(1)y_(1)+by_(1)^(2)|)/(sqrt((a-b)^(2)+4h^(2)))`
    B
    `(|ax_(1)^(2)+2hx_(1)y_(1)+by_(1)^(2)|)/(sqrt((a-b)^(2)+h^(2)))`
    C
    `(|ax_(1)^(2)+2hx_(1)y_(1)+by_(1)^(2)|)/(sqrt((a+b)^(2)+4h^(2)))`
    D
    `(|ax_(1)^(2)-2hxy_(1)y_(1)+by_(1)^(2)|)/(sqrt((a-b)^(2)+4h^(2)))`
  • If the product of the perpendiculars drawn from the point (1,1) on the lines ax^(2)+2hxy+by^(2)=0 is 1, then

    A
    `h(a-b)+ab=0`
    B
    `h(a+b)-ab=0`
    C
    `h(a+b)+ab=0`
    D
    `h(a-b)-ab=0`
  • Foot of the perpendicular from a point (x_(1),y_(1)) on the line ax + by + c= 0 is given by

    A
    `(x-x_(1))/(a)=(y-y_(1))/(b)=((ax_(1)+by_(1)+c)/(a^(2)+b^(2)))`
    B
    `(x-x_(1))/(a)=(y-y_(1))/(b)=((ax_(1)+by_(1)+c)/(sqrt(a^(2)+b^(2))))`
    C
    `(x-x_(1))/(a)=(y-y_(1))/(b)=-((ax_(1)+by_(1)+c)/(a^(2)+b^(2)))`
    D
    `(x-x_(1))/(a)=(y-y_(1))/(b)=((ax_(1)+by_(1)+c)/(sqrt(a^(2)+b^(2))))`
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