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Π ∫ 0 ( Sin 2 X 2 − Cos 2 X 2 ) D X

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Question

\[\int\limits_0^\pi \left( \sin^2 \frac{x}{2} - \cos^2 \frac{x}{2} \right) dx\]
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Solution

\[Let\ I = \int_0^\pi \left( \sin^2 \frac{x}{2} - \cos^2 \frac{x}{2} \right) d\ x\ . Then, \]
\[I = - \int_0^\pi \cos\ x\ dx\ \left[ \because \cos A = \cos^2 \frac{A}{2} - \sin^2 \frac{A}{2} \right]\]
\[ \Rightarrow I = - \left[ \sin x \right]_0^\pi \]
\[ \Rightarrow I = 0\]

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Chapter 19: Definite Integrals - Exercise 20.1 [Page 17]

APPEARS IN

R.D. Sharma Mathematics Volume 1 and 2 [English] Class 12
Chapter 19 Definite Integrals
Exercise 20.1 | Q 57 | Page 17

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