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The direction ratios of a line are (-2, ...

The direction ratios of a line are (-2, 3, 6). If the line makes an acute angle with positive direction of x-axis
then the modulus of integral value of sum of all direction cosines, is _________.

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The correct Answer is:
To solve the problem, we will follow these steps: ### Step 1: Understand Direction Ratios and Direction Cosines The direction ratios of the line are given as (-2, 3, 6). The direction cosines (L, M, N) are calculated using the formula: \[ L = \frac{a}{\sqrt{a^2 + b^2 + c^2}}, \quad M = \frac{b}{\sqrt{a^2 + b^2 + c^2}}, \quad N = \frac{c}{\sqrt{a^2 + b^2 + c^2}} \] where \( a, b, c \) are the direction ratios. ### Step 2: Calculate the Magnitude of Direction Ratios First, we need to calculate the magnitude of the direction ratios: \[ \sqrt{(-2)^2 + 3^2 + 6^2} = \sqrt{4 + 9 + 36} = \sqrt{49} = 7 \] ### Step 3: Calculate Direction Cosines Now we can calculate the direction cosines: - For L: \[ L = \frac{-2}{7} \] - For M: \[ M = \frac{3}{7} \] - For N: \[ N = \frac{6}{7} \] ### Step 4: Sum of Direction Cosines Next, we find the sum of the direction cosines: \[ L + M + N = \frac{-2}{7} + \frac{3}{7} + \frac{6}{7} \] ### Step 5: Simplify the Sum Now, simplifying the sum: \[ L + M + N = \frac{-2 + 3 + 6}{7} = \frac{7}{7} = 1 \] ### Step 6: Calculate the Modulus Finally, we need the modulus of the sum: \[ |L + M + N| = |1| = 1 \] ### Final Answer The modulus of the integral value of the sum of all direction cosines is: \[ \boxed{1} \] ---
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Knowledge Check

  • Angle 6 made by the line with positive direction of X-axis is 45^(@) then the slope of line is…..

    A
    1
    B
    2
    C
    `(1)/(2)`
    D
    `(1)/(sqrt2)`
  • The equation of a line which passes through (2,3) and makes an angle of 30^(@) with the positive direction of x-axis is

    A
    `x-sqrt3y+3sqrt3-2=0`
    B
    `x-sqrt3y=2`
    C
    `x+sqrt3y+3sqrt3-2=0`
    D
    `x-sqrt3y-3sqrt2-2=0`
  • The sum of the direction cosines of a line which makes equal angles with the positive direction of co-ordinate axes is

    A
    3
    B
    1
    C
    `sqrt(3)`
    D
    `(3)/(sqrt(2))`
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