Question: Find the equation of lines which pass through the point (1,0) and perpendicular to the lines represented by x²-xy-2y²=0.
Solution:
Given,
Single equation of lines is x^2 -xy -2y^2 = 0
Point P(x_1,y_1) = (1,0)
Finding separate equations of lines:
x^2 -xy -2y^2 = 0
or, x^2 -(2-1)xy -2y^2 = 0
or, x^2 - 2xy +xy -2y^2 = 0
or, x(x -2y) +y(x -2y) = 0
or, (x -2y)(x +y) = 0
So, the separate equations of straight lines are (x -2y = 0) and (x +y = 0).
For line 1,
Equation: (x -2y = 0)
Slope (m_1) = \frac{1}{2}
Slope of perpendicular line (m_2) = -2
Point P(x_1,y_1) = (1,0)
Equation of perpendicular line is given by:
y - y_1= m_2(x -x_1)
$or, y -0 = -2(x -1)$
or, y= -2x +2
or, 2x +y -2 = 0 is the required equation.
For line 2,
Equation: (x +y= 0)
Slope (m_1) = -1
Slope of perpendicular line (m_2) = 1
Point P(x_1,y_1) = (1,0)
Equation of perpendicular line is given by:
y - y_1 = m_2(x -x_1)
or, y -0 = 1(x -1)
or, y= x-1
or, x - y -1 = 0 is the required equation.
Therefore, the required equations of the straight lines are (2x +y -2 = 0) and (x - y -1 = 0).
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