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Find the general solution of the following equation: 4 cos^2 θ = 3 - Mathematics and Statistics

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Question

Find the general solution of the following equation:

4 cos2 θ  = 3

Sum
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Solution

The general solution of cos2θ = cos2α is θ = nπ ± α, n ∈ Z.

Now, 4 cos2 θ  = 3

∴ `cos^2θ = (3)/(4) = (sqrt(3)/2)^2`

∴ `cos^2θ = (cos  π/(6))^2`   ...`[∵ cos  π/6 = sqrt(3)/(2)]`

∴ `cos^2θ = cos^2  π/6`

∴ The required general solution is given by `θ = nπ ± (π)/(6), n ∈ Z`.

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Trigonometric Equations and Their Solutions
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Chapter 3: Trigonometric Functions - Exercise 3.1 [Page 75]

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