Question

COS(A+B).COS(A-B)=

Please answer fast and I will follow you .
90 marks question ​

Answer 1

$cos(a + b) \times cos(a - b) \\ = {cos}^{2} a - {sin}^{2} b \\ = {cos}^{2} b - {sin}^{2} a$

{here a=A and b=B}

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Answer 2

Step-by-step explanation:

Here your answer