Question: What is $ \sqrt{\frac{1+\sin \theta }{1-\sin \theta }} $ equal to?
Options:
A) $ \sec \theta -\tan \theta $
B) $ \sec \theta +\tan \theta $
C) $ \cos ec\theta +\cot \theta $
D) $ \cos ec\theta -\cot \theta $
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Answer:
Correct Answer: B
Solution:
- $ \sqrt{\frac{1+\sin \theta }{1-\sin \theta }} $
On multiplying with $ 1+\sin \theta $ in numerator and denominator, we get
$ \sqrt{\frac{(1+\sin \theta )}{(1-\sin \theta )}\times \frac{(1+\sin \theta )}{(1+\sin \theta )}} $
$ =\sqrt{\frac{{{(1+\sin \theta )}^{2}}}{1-{{\sin }^{2}}\theta }}=\sqrt{\frac{{{(1+\sin \theta )}^{2}}}{{{\cos }^{2}}\theta }} $
$ \Rightarrow $ $ \frac{1+\sin \theta }{\cos \theta }=\frac{1}{\cos \theta }+\frac{\sin \theta }{\cos \theta } $
$ =\sec \theta +\tan \theta $