Prove that (i) cos^2 30° + sin 30° + tan^2 45° = 2 1/4 (ii) 4(sin^4 30° + cos^4 60°) - 3(cos^2 45° - sin^2 90°) = 2 (iii) cos 60° = cos^2 30° - sin^2 30°.sin<sup>2</sup> 30°.

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If x = 15°, verify that 4 sin 2x cos 4x sin 6x = 1.