If cos4αcos4β+ sin4αsin4β = 1, prove that (i) sin2α +sin2β =2sin2α sin2β .

If $\frac{\cos^{4} α}{\cos^{4} β} + \frac{\sin^{4} α}{\sin^{4} β} = 1$ , prove that (i) $\sin^{2} α + \sin^{2} β = 2 \sin^{2} α \sin^{2} β$ .

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