Question

(cos + sin )2 h ( cos - sin )2=2 prove the
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Answer 1

Step-by-step explanation:

(cos+sin)²+(cos-sin)²

(cos²+sin²+2sin•cos)+(cos²+sin²-2sin•cos)

cos²+cos²+sin²+sin²+2sin•cos-2sin•cos

2cos²+2sin²

2(cos²+sin²)

2×1

2

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