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If the distance of a point (x(1),y(1)) f...

If the distance of a point `(x_(1),y_(1))` from each of the two straight lines, which pass through the origin of coordinates, is `delta`, then the two lines are given by

A

`(x_(1)y-xy_(1))^(2)=delta^(2)(x^(2)+y^(2))`

B

`(x_(1)y+xu_(1))^(2)=delta^(2)(x^(2)+y^(2))`

C

`(x_(1)y-xy_(1))^(2)=delta^(2)(x^(2)-y^(2))`

D

none of these

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The correct Answer is:
To find the two lines that pass through the origin and are at a distance of \(\delta\) from the point \((x_1, y_1)\), we can follow these steps: ### Step-by-Step Solution: 1. **Equation of the Line**: The lines passing through the origin can be expressed in the form \(y = mx\), where \(m\) is the slope of the line. Therefore, the equation of the line can be rewritten as: \[ mx - y = 0 \] 2. **Distance Formula**: The distance \(d\) from a point \((x_1, y_1)\) to the line \(Ax + By + C = 0\) is given by: \[ d = \frac{|Ax_1 + By_1 + C|}{\sqrt{A^2 + B^2}} \] For our line \(mx - y = 0\), we have \(A = m\), \(B = -1\), and \(C = 0\). Thus, the distance from the point \((x_1, y_1)\) to the line is: \[ \delta = \frac{|mx_1 - y_1|}{\sqrt{m^2 + 1}} \] 3. **Squaring Both Sides**: To eliminate the square root, we square both sides: \[ \delta^2 = \frac{(mx_1 - y_1)^2}{m^2 + 1} \] 4. **Cross Multiplication**: Cross-multiplying gives: \[ \delta^2(m^2 + 1) = (mx_1 - y_1)^2 \] 5. **Expanding the Right Side**: Expanding the right side: \[ \delta^2 m^2 + \delta^2 = m^2x_1^2 - 2mx_1y_1 + y_1^2 \] 6. **Rearranging the Equation**: Rearranging gives: \[ m^2(x_1^2 - \delta^2) - 2mx_1y_1 + (y_1^2 - \delta^2) = 0 \] 7. **Quadratic in m**: This is a quadratic equation in \(m\): \[ m^2(x_1^2 - \delta^2) - 2mx_1y_1 + (y_1^2 - \delta^2) = 0 \] 8. **Using the Quadratic Formula**: The solutions for \(m\) can be found using the quadratic formula: \[ m = \frac{-(-2x_1y_1) \pm \sqrt{(-2x_1y_1)^2 - 4(x_1^2 - \delta^2)(y_1^2 - \delta^2)}}{2(x_1^2 - \delta^2)} \] 9. **Final Result**: The two lines are given by the slopes \(m_1\) and \(m_2\) obtained from the quadratic equation above.

To find the two lines that pass through the origin and are at a distance of \(\delta\) from the point \((x_1, y_1)\), we can follow these steps: ### Step-by-Step Solution: 1. **Equation of the Line**: The lines passing through the origin can be expressed in the form \(y = mx\), where \(m\) is the slope of the line. Therefore, the equation of the line can be rewritten as: \[ mx - y = 0 ...
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OBJECTIVE RD SHARMA ENGLISH-PAIR OF STRAIGHT LINES-Section I - Solved Mcqs
  1. Show that the condition that two of the three lines represented by ax^...

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  2. The orthocentre of the triangle formed by the pair of lines 2x^(2)-xy-...

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  3. If the distance of a point (x(1),y(1)) from each of the two straight l...

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  4. The equation of two straight lines through the point (x(1),y(1)) and p...

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  5. The equation of the straigh lines through the point (x(1),y(1)) and pa...

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  6. The triangle formed by the lines whose combined equation is (y^2 - 4xy...

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  7. Find the combined equation of the pair of lines through the point (1, ...

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  8. The equation x^(3)+ax^(2)y+bxy^(2)+y^(3)=0 represents three straight l...

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  9. The combined equation of the lines L(1) and L(2) is 2x^(2)+6xy+y^(2)=0...

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  10. The lines represented by x^(2)+2lambda xy+2y^(2)=0 and the lines repre...

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  11. Prove that the equation m (x^3-3xy^2)+y^3-3x^2y=0 represents three str...

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  12. If the equation x^(4)+bx^(3)y+cx^(2)y^(2)+dxy^(3)+ey^(4)=0 represent t...

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  13. The equation x^(3)+x^(2)y-xy^(2)-y^(3)=0 represents three straight lin...

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  14. If one of the lines of my^(2)+(1-m^(2))xy-mx^(2)=0 is a bisector of th...

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  15. The equation x^2 - 3xy+ lambday^2 + 3x - 5y + 2 = 0 where lambda is a ...

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  16. If the line y = mx bisects the angle between the lines ax^2 + 2h xy ...

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  17. Two pairs of straight lines have the equations y^(2)+xy-12x^(2)=0andax...

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  18. The point of intersection of the pair of straight lines given by 6x^(2...

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  19. The straight lines represented by x^2+m x y-2y^2+3y-1=0 meet at (a) (-...

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  20. The square of the distance between the origin and the point of interse...

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