How do you verify that the x values $pi/3, (5pi)/3$ are solutions to $2cosx-1=0$ ?

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Answer 1 · 2017-02-27T05:36:30

Use trig table of special arcs -->
When $x = pi/3$ --> $cos (pi/3) = 1/2$
$2cos x - 1 = 2/2 - 1 = 0$ . Proved

When $x = (5pi)/3$ --> $cos ((5pi)/3) = cos (pi/3) = 1/2$
$2cos x - 1 = 2/2 - 1 = 0$ . Proved

How do you verify that the x values pi/3, (5pi)/3pi/3, (5pi)/3 are solutions to 2cosx-1=02cosx-1=0?