SSC Sample Paper SSC CHSL (10+2) Sample Test Paper-9

  • question_answer
    The value of\[\frac{\sin \,43{}^\circ }{\cos 47{}^\circ }+\frac{\cos \,19{}^\circ }{\sin \,71{}^\circ }-8\,{{\cos }^{2}}60{}^\circ \] is

    A) 0                                 

    B) 1

    C) 2                     

    D) \[-1\]

    Correct Answer: A

    Solution :

    Expression \[=\frac{\sin \,43{}^\circ }{\cos 47{}^\circ }+\frac{\cos 19{}^\circ }{\sin \,\,71{}^\circ }-8{{\cos }^{2}}60{}^\circ \] \[=\frac{\sin \,43{}^\circ }{\cos (90{}^\circ -43{}^\circ )}+\frac{\cos \,19{}^\circ }{\sin (90{}^\circ -19{}^\circ )}\]                         \[-8\times {{\left( \frac{1}{2} \right)}^{2}}\] \[=\frac{\sin \,43{}^\circ }{\sin \,43{}^\circ }+\frac{\cos 19{}^\circ }{\cos 19{}^\circ }-8\times \frac{1}{4}\]             \[[\sin \,(90{}^\circ -\theta )=\cos \theta :\]             \[\cos \,(90{}^\circ -\theta )=\sin \theta ]\] \[=1+1-2=0\]


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