2. Solved Papers
  3. JAMIA MILLIA ISLAMIA

JAMIA MILLIA ISLAMIA Jamia Millia Islamia Solved Paper-2015

  • question_answer
    If tangents drawn to the ellipse through point \[=F[(-\hat{i}\times \hat{k})+(\hat{j}\times \hat{k})]\]to the ellipse \[=F[\hat{j}+\hat{i}]=F[\hat{i}+\hat{j}]\]are at right angled, then value of b is

    A) 1                                             

    B) 4

    C)  2 

    D) None of these

    Correct Answer: C

    Solution :

    Since, tangents drawn from\[(1,2,\sqrt{3})\]to the ellipse\[\frac{{{x}^{2}}}{{{a}^{2}}}+\frac{{{y}^{2}}}{{{b}^{2}}}=1\]are right angled, therefore  will lie on the > direction circle of the ellipse. So, \[(1,2,\sqrt{3})\]will lie on \[{{x}^{2}}+{{y}^{2}}=9+{{b}^{2}}\]. \[\therefore \]  \[1+12=9+{{b}^{2}}\] \[\Rightarrow \]               \[{{b}^{2}}=4\] \[\Rightarrow \]               \[b=2\]                                


You need to login to perform this action.
You will be redirected in 3 sec spinner