trigonometric functions

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find all the values of x which satisfies 0<x<360 , cos 3x=0.39 ?

Guest Jul 29, 2013

scrutinizer · Answer 1 · 2013-08-26T03:33:38

cos 3x=0.39 = > y = 3x -> cos y = 0.39 => y = +-[arccos (0.39) + 2 pi n] => 3x = +-arccos (0.39) + 2 pi n -> x = +-1/3[arccos (0.39)] +- (2 pi n/3)

cos (3x)=0.39