2 cos 11
√2 + √2 + √2
4
Answers
Answered by
0
Answer:
Step-by-step explanation:
cos
2
A
=
2
cos
2
A
−
1
, we have
cos
8
θ
=
2
cos
2
(
4
θ
)
−
1
,
cos
4
θ
=
2
cos
2
(
2
θ
)
−
1
and
cos
2
θ
=
2
cos
2
θ
−
1
i.e.
1
+
cos
8
θ
=
2
cos
2
(
4
θ
)
,
1
+
cos
4
θ
=
2
cos
2
(
2
θ
)
and
1
+
cos
2
θ
=
2
cos
2
θ
Hence
√
2
+
√
2
+
√
2
+
2
cos
8
θ
=
√
2
+
√
2
+
√
2
(
1
+
cos
8
θ
)
=
√
2
+
√
2
+
√
2
×
2
cos
2
(
4
θ
)
=
√
2
+
√
2
+
2
cos
(
4
θ
)
=
√
2
+
√
2
(
1
+
cos
(
4
θ
)
)
=
√
2
+
√
2
×
2
cos
2
(
2
θ
)
=
√
2
+
2
cos
2
θ
=
√
2
(
1
+
cos
2
θ
)
=
√
2
×
2
cos
2
θ
=
2
cos
θ
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