BITSAT 2024Paper 1
- Exam
- BITSAT
- Year
- 2024
- Paper
- Paper 1
- Subject
- Mathematics
- Chapter
- Inverse Trigonometric Functions
BITSAT 2024 · Paper 1 · Mathematics · Inverse Trigonometric Functions
If ^ -1 ((1)/(2))= ( ^ -1 x) , then the value of x is
If , then the value of
Options
- A
- B
- C
- D
Correct answer
A.
Step-by-step solution
We have
\cos \left(\cot ^{-1}\left(\frac{1}{2}\right)\right)=\cot \left(\cos ^{-1}x\right)$
Let $\cot $^{-1}\left(\frac{1}{2}\right)=\alpha \Rightarrow \cot \alpha=\frac{1}{2} \Rightarrow \cos ^{-1} \frac{1}{\sqrt{5}}\Rightarrow \cos \left(\cos ^{-1} \frac{1}{\sqrt{5}}\right)=\cot \left(\cot ^{-1} \frac{x}{\sqrt{1-x^2}}\right)\Rightarrow \frac{1}{\sqrt{5}}=\frac{x}{\sqrt{1-x^2}} \Rightarrow \sqrt{1-x^2}=\sqrt{5}x1-x²=5 x² \Rightarrow 1=6 x²\Rightarrow x= \frac{1}{\sqrt{6}}$