Question
Find the value of $'A\ ',$ if $2\cos 3A = 1$
✓
Answer
$ 2 \cos 3 A =1$
$ \Rightarrow \cos 3A =\frac{1}{2}$
$ \Rightarrow \cos 3A =\cos 60^{\circ}$
$ \Rightarrow 3A =60^{\circ}$
$ \Rightarrow A =20^{\circ} .$
$ \Rightarrow \cos 3A =\frac{1}{2}$
$ \Rightarrow \cos 3A =\cos 60^{\circ}$
$ \Rightarrow 3A =60^{\circ}$
$ \Rightarrow A =20^{\circ} .$
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