Q.17 is equal to - 1 - cos 4a 1+cos...
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Q.17 is equal to - 1 - cos 4a 1+cos 4a sec? 2a -1 cosec? 2a -1 (A) 0 (B) 2 (C)1 (D) 4 Conditional Tria identiti.

JEE/Engineering Exams
Maths
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( frac{1-cos 4 alpha}{sec ^{2} 2 alpha-1}+frac{1+cos 4 alpha}{operatorname{cosec}^{2} 2 alpha-1} ) ( 1-cos u alpha=2 sin ^{2} theta alpha ) ( 1+cos 4 x=2 cos ^{2} 2 x ) ( frac{2 sin ^{2} 2 alpha}{sec ^{2} 2 alpha-1}+frac{2 cos ^{2} 2 alpha}{operatorname{cosec}^{2} 2 alpha-1} ) ( Rightarrow quad 2 sin ^{2} 2 alpha operatorname{cosec}^{2} 2 alpha-2 sin ^{2} 2 alpha+2 cos ^{2} 2 alpha sec ^{2} alpha ) ( -2 cos ^{2} 2 alpha ) ( left(sec ^{2} 2 alpha-1right)left(operatorname{cosec}^{2} 2 alpha-1right) ) ( Rightarrow frac{4-2 sin ^{2} 2 alpha-2 cos ^{2} 2 alpha}{tan ^{2} 2 alpha cdot cot ^{2} 2 alpha}left[begin{array}{c}0.0 sec ^{2} 2 alpha-1 =tan ^{2} alphaend{array}right. ) ( =4-2 operatorname{csin}^{2} 2 alpha+cos ^{2} 2 alpha ) ( =cot ^{2} 2 x ) ( =4-2=2 )
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