Question : If $\sin \theta=\frac{5}{13}$, then what is the value of $\frac{\cos ^{2} \theta-\sin ^{2} \theta}{2 \cos \theta \cdot \sin \theta}?$
Option 1: $\frac{117}{136}$
Option 2: $\frac{113}{120}$
Option 3: $\frac{115}{126}$
Option 4: $\frac{119}{120}$
Recommended: How to crack SSC CHSL | SSC CHSL exam guide
Don't Miss: Month-wise Current Affairs | Upcoming government exams
Correct Answer: $\frac{119}{120}$
Solution :
Given,
$\sin \theta=\frac{5}{13}$
We know, $\cos\theta=\sqrt{1-\sin^2\theta}$
⇒ $\cos\theta=\sqrt{1-\frac{5^2}{13^2}}$
⇒ $\cos\theta=\sqrt{\frac{13^2-{5^2}}{13^2}}$
⇒ $\cos\theta=\frac{\sqrt{13^2-5^2}}{13}$
⇒ $\cos\theta=\frac{\sqrt{169-25}}{13}$
⇒ $\cos\theta=\frac{12}{13}$
$\therefore\frac{\cos ^{2} \theta-\sin ^{2} \theta}{2 \cos \theta \cdot \sin \theta}=\frac{\frac{12^2}{13^2}-\frac{5^2}{13^2}}{2\times\frac{12}{13}\times\frac{5}{13}}=\frac{144-25}{2\times12\times5}=\frac{119}{120}$
Hence, the correct answer is $\frac{119}{120}$.
Related Questions
Know More about
Staff Selection Commission Combined High ...
Answer Key | Eligibility | Application | Admit Card | Preparation Tips | Result | Cutoff
Get Updates BrochureYour Staff Selection Commission Combined Higher Secondary Level Exam brochure has been successfully mailed to your registered email id “”.




