Question : If $3 x=\sec A$ and $\frac{3}{x}=\tan A$, then $9\left(x^2-\frac{1}{x^2}\right)$ is:
Option 1: $3$
Option 2: $9$
Option 3: $1$
Option 4: $\frac{1}{9}$
Latest: SSC CGL preparation tips to crack the exam
Don't Miss: SSC CGL complete guide
Correct Answer: $1$
Solution :
We know that,
$\sec ^2A-\tan^2 A=1$
⇒ $(3x)^2-(\frac{3}{x})^2=1$
⇒ $9x^2-\frac{9}{x^2}=1$
⇒ $9\left(x^2-\frac{1}{x^2}\right)=1$
Hence, the correct answer is $1$.
Related Questions
Know More about
Staff Selection Commission Combined Grad ...
Answer Key | Eligibility | Application | Selection Process | Preparation Tips | Result | Admit Card
Get Updates BrochureYour Staff Selection Commission Combined Graduate Level Exam brochure has been successfully mailed to your registered email id “”.