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Plzzzzzzzz try to an this question .....we have to prove the given question |
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Answer» I am taking alpha as x and beta as y for convenience :3 Now onto the question, COSY cos(2x-y) = cos²x -sin²(x-y) Taking RHS FIRST, cos²x-sin²(x-y) we KNOW, by identity, cos²a - sin²b = cos(a-b)cos(a+b) Now, putting this identity in USE in RHS we GET, cos²x - sin²(x-y) =>cos(x-(x-y)) cos(x+x+y) =>cos(x-x+y) cos(2x+y) =>cos y cos(2x+y) = LHS Cheers! |
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