3
(ii) cos2 A + cos2 (60° + A) + cos² (60° – A)
11
2​

Step-by-step explanation:

Answer:

\huge\boxed{\bf \implies \frac{3}{2} }

⟹

2

3

Step-by-step explanation:

\begin{gathered} \bf \:{ cos}^{2}0°+{cos }^{2}60°+{cos}^{2}90° \\ \\ \bf \implies {1}^{2} + { \frac{1}{2} }^{2} + {0}^{2} \\ \\ \bf \implies \frac{2 + 1 + 0}{2} \\ \\ \boxed{\bf \implies \frac{3}{2} }\end{gathered}

cos

2

0°+cos

2

60°+cos

2

90°

⟹1

2

+

2

1

2

+0

2

⟹

2

2+1+0

⟹

2

3

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