CET Karnataka Engineering CET - Karnataka Engineering Solved Paper-2006

  • question_answer
    Which one of the following equations has no solution?

    A)  \[\cos ec\theta -\sec \theta =\cos ec\theta \,.\,\,\sec \theta \]

    B)  \[\cos ec\theta \,.\,\,\sec \theta =1\]

    C)                  \[\cos \theta +\sin \theta =\sqrt{2}\]

    D)  \[\sqrt{3}\,\sin \theta -\cos \theta =2\]

    Correct Answer: B

    Solution :

     \[\text{cosec }\theta \text{-sec}\theta \text{=cosec}\theta \text{.sec}\theta \] \[\Rightarrow \]               \[\frac{\cos \,\theta -\sin \,\theta }{\cos \theta \,sin\theta }=\frac{1}{\cos \,\theta \,\sin \theta }\] \[\Rightarrow \]               \[\cos \,\theta =1+\sin \theta \] \[\therefore \] At \[\theta =0\] above equation satisfies.     \[\text{cosec}\,\theta \text{.}\,\text{sec}\theta \text{=1}\] \[\Rightarrow \]               \[\sin \theta \,\cos \theta =1\] \[\Rightarrow \]               \[2\,\sin \theta \,\,\cos \theta =2\] \[\Rightarrow \]               \[\sin \,2\theta =2\] As we know sin 9 is not greater than 1. \[\therefore \] The above equation has no solution exist.


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