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If \(y=\frac{2 \sin \alpha}{1+\cos \alpha+\sin \alpha}\), then value of \(\frac{1-\cos \alpha+\sin \alpha}{1+\sin \alpha}\) is
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The correct answer is:
\(\mathrm{y}\)
\(\begin{aligned}
& \frac{1-\cos \alpha+\sin \alpha}{1+\sin \alpha} \\
& =\frac{1-\cos \alpha+\sin \alpha}{1+\sin \alpha} \cdot \frac{1+\cos \alpha+\sin \alpha}{1+\cos \alpha+\sin \alpha} \\
& =\frac{(1+\sin \alpha)^2-\cos ^2 \alpha}{(1+\sin \alpha)(1+\cos \alpha+\sin \alpha)} \\
& =\frac{2 \sin \alpha(1+\sin \alpha)}{(1+\sin \alpha)(1+\cos \alpha+\sin \alpha)} \\
& =\frac{2 \sin \alpha}{1+\cos \alpha+\sin \alpha}=y
\end{aligned}\)
& \frac{1-\cos \alpha+\sin \alpha}{1+\sin \alpha} \\
& =\frac{1-\cos \alpha+\sin \alpha}{1+\sin \alpha} \cdot \frac{1+\cos \alpha+\sin \alpha}{1+\cos \alpha+\sin \alpha} \\
& =\frac{(1+\sin \alpha)^2-\cos ^2 \alpha}{(1+\sin \alpha)(1+\cos \alpha+\sin \alpha)} \\
& =\frac{2 \sin \alpha(1+\sin \alpha)}{(1+\sin \alpha)(1+\cos \alpha+\sin \alpha)} \\
& =\frac{2 \sin \alpha}{1+\cos \alpha+\sin \alpha}=y
\end{aligned}\)
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