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

  • question_answer
    Is \[\frac{1-\sin \theta }{1+\sin \theta }={{\sec }^{2}}\theta -{{\tan }^{2}}\theta \]?

    A) True

    B) False

    C) Cannot say

    D) Partially True/False

    Correct Answer: B

    Solution :

    (False) We have, \[\frac{1-\sin \theta }{1+\sin \theta }=\frac{\left( 1-\sin \theta  \right)\left( 1-\sin \theta  \right)}{\left( 1+\sin \theta  \right)\left( 1-\sin \theta  \right)}\] \[\left[ \because \,\,rationalise \right]\] \[\Rightarrow \,\,\frac{{{\left( 1-\sin \theta  \right)}^{2}}}{1-{{\sin }^{2}}\theta }={{\left( \frac{1-\sin \theta }{\cos \theta } \right)}^{2}}\] \[\left[ \because \,{{\sin }^{2}}\theta +{{\cos }^{2}}\theta =1 \right]\] \[={{\left( \sec \theta -\tan \theta  \right)}^{2}}\] \[LHS\ne RHS\]


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