Q
quynhnhu_16


1. [TEX]cos^2\alpha(cos^4\alpha + sin^2\alpha.cos^2\alpha + sin^2\alpha + tan^2 \alpha) = 1[/TEX]
2. [TEX]( 1- sin^2\alpha).cot^2\alpha + (1-cot^2\alpha) = sin^2\alpha [/TEX]
3.[TEX]\frac{2.cos^2\alpha -1}{sin\alpha + cos\alpha }= cos\alpha - sin\alpha[/TEX]
2. [TEX]( 1- sin^2\alpha).cot^2\alpha + (1-cot^2\alpha) = sin^2\alpha [/TEX]
3.[TEX]\frac{2.cos^2\alpha -1}{sin\alpha + cos\alpha }= cos\alpha - sin\alpha[/TEX]
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