Question : If $2 \frac{\cos ^2 x-\sec ^2 x}{\tan ^2 x}=a+b \cos 2 x$, then $a, b=$?
Option 1: $-\frac{3}{2}, -\frac{1}{2}$
Option 2: $\frac{3}{2}, \frac{1}{2}$
Option 3: $-3, -1$
Option 4: $3,1$
Latest: SSC CGL 2024 final Result Out | SSC CGL preparation tips to crack the exam
Don't Miss: SSC CGL Tier 1 Scorecard 2024 Released | SSC CGL complete guide
Suggested: Month-wise Current Affairs | Upcoming Government Exams
Correct Answer: $-3, -1$
Solution : $2 \frac{\cos ^2 x-\sec ^2 x}{\tan ^2 x}$ = $2 \frac{\cos ^2 x-\frac{1}{\cos ^2 x}}{\tan ^2 x}$ = $2 \frac{\cos ^4 x - 1}{\tan ^2 x\cos ^2 x}$ = $2 \frac{(\cos ^2 x - 1)(\cos ^2 x + 1)}{\frac{\sin^2 x}{\cos^2 x}\cos ^2 x}$ We know that $\sin ^2 x + \cos ^2 x=1$ = $2 \frac{(-\sin ^2 x)(\cos ^2 x + 1)}{\sin^2 x}$ So, $2 \frac{\cos ^2 x-\sec ^2 x}{\tan ^2 x} = -2\cos ^2 x-2$ We know that $\cos ^2 x = \frac{(1+\cos 2x)}{2}$ So, $2 \frac{\cos ^2 x-\sec ^2 x}{\tan ^2 x} =-2\frac{(1+\cos 2x)}{2}-2=-3-\cos 2x$ Thus, $a+b\cos2x=-3-\cos 2x$ By comparing we get, $a = -3$ and $b= -1$ Hence, the correct answer is $-3, -1$.
Candidates can download this ebook to know all about SSC CGL.
Admit Card | Eligibility | Application | Selection Process | Preparation Tips | Result | Answer Key
Question : The value of $\sec x - \cos x = $?
Option 1: $\tan x \sin x$
Option 2: $\sec x \tan x$
Option 3: $\tan x \cos x$
Option 4: $\sec x \cos x$
Question : If $\tan \frac{A}{2}=x$, then find $x$.
Option 1: $\frac{\sqrt{1+\cos A}}{\sqrt{1-\cos A}}$
Option 2: $\frac{\sqrt{1-\sin A}}{\sqrt{1+\cos A}}$
Option 3: $\frac{\sqrt{1-\cos A}}{\sqrt{1+\cos A}}$
Option 4: $\frac{\sqrt{\cos A-1}}{\sqrt{1+\cos A}}$
Question : If $\tan A \tan B+\frac{\cos x}{\cos A \cos B}=1$, then $x=?$
Option 1: $B$
Option 2: $A$
Option 3: $A + B$
Option 4: $A - B$
Question : If $\cos x+\sec x=\frac{7}{2 \sqrt{3}}$, then the value of $\cos ^2 x+\sec ^2 x$ will be_____.
Option 1: $\frac{15}{12}$
Option 2: $\frac{10}{12}$
Option 3: $\frac{25}{10}$
Option 4: $\frac{25}{12}$
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: $\frac{1}{9}$
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile