10th Class Mathematics Introduction to Trigonometry Question Bank Introduction to Trigonometry

  • question_answer
    Find the value of \[\frac{1}{\tan \theta }+\frac{\sin \theta }{1+\cos \theta },\] if \[1+{{\cot }^{2}}\theta ={{(\sqrt{3+2\sqrt{2}}-1)}^{2}}.\]

    A) 2                                 

    B) 3                     

    C) \[-2\]               

    D)        1

    Correct Answer: A

    Solution :

    We have,  \[1+{{\cot }^{2}}\theta ={{(\sqrt{3+2\sqrt{2}}-1)}^{2}}\] \[\cos e{{c}^{2}}\theta ={{(\sqrt{2+1+2\sqrt{2}}-1)}^{2}}\] \[={{\left( \sqrt{{{(\sqrt{2}+1)}^{2}}}-1 \right)}^{2}}={{(\sqrt{2}+1-1)}^{2}}={{(\sqrt{2})}^{2}}\] \[\Rightarrow \]    \[\cos ec\,\theta =2\] \[\sin \theta =\frac{1}{2},\cos \theta =\frac{\sqrt{3}}{2},\tan \theta =\frac{1}{\sqrt{3}}\] Now, \[\frac{1}{\tan \theta }+\frac{\sin \theta }{1+\cos \theta }=\sqrt{3}+\frac{1/2}{1+\sqrt{3}/2}=2\]


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