Railways Sample Paper RRBs Assistant Loco Pilot and Technician CBT STAGE-I Sample Paper-11

  • question_answer
    If \[x=\frac{\sin \theta .cos\theta \left( 90{}^\circ -\theta  \right)+\cos \theta .\sin \left( 90{}^\circ -\theta  \right)}{\tan \theta .\sec \left( 90{}^\circ -\theta  \right).\sin \left( 90{}^\circ -\theta  \right)}\] What will be the value of x?

    A)  1        

    B)         \[-1\]

    C)  2                    

    D)  \[-2\]

    Correct Answer: A

    Solution :

    \[x=\frac{\sin \theta \cos \left( 90{}^\circ -\theta  \right)+\cos \theta \sin \left( 90{}^\circ -\theta  \right)}{\tan \theta \sec \theta \left( 90{}^\circ -\theta  \right)\sin \left( 90{}^\circ -\theta  \right)}\] \[=\frac{\sin \theta sin\theta +\cos \theta \cos \theta }{\tan \theta \cos \theta .\operatorname{cosec}\theta }=\frac{{{\sin }^{2}}\theta +{{\cos }^{2}}\theta }{\frac{\sin \theta }{\cos \theta }\cdot \cos \theta \cdot \frac{1}{\sin \theta }}\] \[=\frac{1}{\frac{\sin \theta \cos \theta }{\sin \theta \cos \theta }}=1\]


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