मराठी

1 / 2 ∫ − 1 / 2 Cos X Log ( 1 + X 1 − X ) D X

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प्रश्न

\[\int\limits_{- 1/2}^{1/2} \cos x \log\left( \frac{1 + x}{1 - x} \right) dx\]

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उत्तर

\[\int_\frac{- 1}{2}^\frac{1}{2} \cos x \log\left( \frac{1 + x}{1 - x} \right) d x\]

\[\text{Let }f(x) = \cos x \log\left( \frac{1 + x}{1 - x} \right)\]

\[\text{Consider }f(- x) = \cos\left( - x \right) \log\left( \frac{1 - x}{1 + x} \right)\]

\[ = \cos x\left\{ - \log\left( \frac{1 + x}{1 - x} \right) \right\} = - \cos x \log\left( \frac{1 + x}{1 - x} \right) = - f\left( x \right)\]

Thus f(x) is an odd function

Therefore,

\[ \int_\frac{- 1}{2}^\frac{1}{2} \cos x \log\left( \frac{1 + x}{1 - x} \right) d x = 0\]

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पाठ 19: Definite Integrals - Revision Exercise [पृष्ठ १२२]

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आर.डी. शर्मा Mathematics Volume 1 and 2 [English] Class 12
पाठ 19 Definite Integrals
Revision Exercise | Q 35 | पृष्ठ १२२

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