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If $\cos α + \cos β = 0 = \sin α + \sin β,$ then $\cos 2 α + \cos 2 β =$

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−2sin⁡(α+β)

−2 cos(α+β)

2 sin⁡(α+β)

2 cos(α+β)

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detailed solution

Correct option is B

(cos⁡α+cos⁡β)2−(sin⁡α+sin⁡β)2=0= cos2⁡α+cos2⁡β+2cos⁡αcos⁡β−sin2⁡α+sin2⁡β+2sin⁡αsin⁡β)=0=cos⁡2α+cos⁡2β=−2(cos⁡αcos⁡β−sin⁡αsin⁡β)=cos⁡2α+cos⁡2β=−2cos⁡(α+β).

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If cos⁡α+cos⁡β=0=sin⁡α+sin⁡β, then cos⁡2α+cos⁡2β=

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If $\cos α + \cos β = 0 = \sin α + \sin β,$ then $\cos 2 α + \cos 2 β =$