JEE Main & Advanced Mathematics Indefinite Integrals Question Bank Fundamental Integration

  • question_answer
    \[\int_{{}}^{{}}{\sqrt{1+\sin x}\ dx=}\] [MP PET 1995]

    A)            \[\frac{1}{2}\left( \sin \frac{x}{2}+\cos \frac{x}{2} \right)+c\]

    B)            \[\frac{1}{2}\left( \sin \frac{x}{2}-\cos \frac{x}{2} \right)+c\]

    C)            \[2\sqrt{1+\sin x}+c\]

    D)            \[-2\sqrt{1-\sin x}+c\]

    Correct Answer: D

    Solution :

               \[\int_{{}}^{{}}{\sqrt{1+\sin x}\,dx}=\int_{{}}^{{}}{\sqrt{{{\left( \sin \frac{x}{2}+\cos \frac{x}{2} \right)}^{2}}}}dx\]            \[=\int_{{}}^{{}}{\sin \frac{x}{2}\,dx}+\int_{{}}^{{}}{\cos \frac{x}{2}\,dx}=-2\cos \frac{x}{2}+2\sin \frac{x}{2}+c\]            \[=-2\left( \cos \frac{x}{2}-\sin \frac{x}{2} \right)+c=-2\sqrt{(1-\sin x)}+c.\]


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