Solve for x : 2 cos 3x - 1 = 0

Sum

2 cos 3x – 1 = 0
cos 3x = `(1)/(2)`
3x = 60°
x = 20°

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Trigonometric Equation Problem and Solution

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Chapter 21: Trigonometrical Ratios [Sine, Consine, Tangent of an Angle and their Reciprocals] - TEST YOURSELF [Page 335]

Chapter 21 Trigonometrical Ratios [Sine, Consine, Tangent of an Angle and their Reciprocals]
TEST YOURSELF | Q 7. (i) | Page 335