Trigonometric EquationHard
Question
A line makes the same angle θ, with each of the x and z axis. If the angle β, which it makes with y-axis, is such that sin2 β = 3sin2 θ, then cos2 θ equals
Options
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Solution
l = cos θ, m = cos θ, n = cos β
cos2 θ + cos2 θ + cos2 β = 1 ⇒ 2 cos2 θ = sin2 β = 3 sin2 θ (given)
cos2 θ = 3/5.
cos2 θ + cos2 θ + cos2 β = 1 ⇒ 2 cos2 θ = sin2 β = 3 sin2 θ (given)
cos2 θ = 3/5.
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