Solve this

Question:

If $\sin \theta=\frac{a}{b}$, show that $(\sec \theta+\tan \theta)=\sqrt{\frac{b+a}{b-a}}$.

 

Solution:

$\mathrm{LHS}=(\sec \theta+\tan \theta)$

$=\frac{1}{\cos \theta}+\frac{\sin \theta}{\cos \theta}$

$=\frac{1+\sin \theta}{\cos \theta}$

$=\frac{1+\sin \theta}{\sqrt{1-\sin ^{2} \theta}}$

$=\frac{\left(1+\frac{a}{b}\right)}{\sqrt{1-\left(\frac{a}{b}\right)^{2}}}$

$=\frac{\left(\frac{1}{1}+\frac{a}{b}\right)}{\sqrt{\frac{1}{1}-\frac{a^{2}}{b^{2}}}}$

$=\frac{\left(\frac{b+a}{b}\right)}{\sqrt{\frac{b^{2}-a^{2}}{b^{2}}}}$

$=\frac{\left(\frac{b+a}{b}\right)}{\left(\frac{\sqrt{b^{2}-a^{2}}}{b}\right)}$

$=\frac{(b+a)}{\sqrt{(b+a)(b-a)}}$

$=\frac{(b+a)}{\sqrt{(b+a)} \sqrt{(b-a)}}$

$=\frac{\sqrt{(b+a)}}{\sqrt{(b-a)}}$

$=\sqrt{\frac{b+a}{b-a}}$

$=\mathrm{RHS}$

Leave a comment

Close

Click here to get exam-ready with eSaral

For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.

Download Now