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Question
Find the value of x, if cos x = cos 60° cos 30° – sin 60° sin 30°
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Solution
cos x = cos 60° cos 30° – sin 60° sin 30°
cos x = `(1/2)(sqrt3/2) - (sqrt3/2)(1/2)`
cos x = 0 = cos 90°
Hence, x = 90°
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