Trigonometric EquationHard
Question
Let L be the line of intersection of the planes 2x + 3y + z = 1 and x + 3y + 2z = 2. If L makes an angles α with the positive x-axis, then cosα equals
Options
A.
B.
C.1
D.
Solution
If direction cosines of L be l, m, n, then
2l + 3m + n = 0
l + 3m + 2n = 0
Solving, we get,
∴ I : m : n =
⇒ cos α = 
2l + 3m + n = 0
l + 3m + 2n = 0
Solving, we get,
∴ I : m : n =
⇒ cos α = Create a free account to view solution
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