Question : If $x=\sqrt[3]{2+\sqrt{3}}$, the value of $x^3+\frac{1}{x^3}$ is:
Option 1: 8
Option 2: 9
Option 3: 2
Option 4: 4
Latest: SSC CGL preparation tips to crack the exam
Don't Miss: SSC CGL complete guide
Correct Answer: 4
Solution :
Given:
$x=\sqrt[3]{2+\sqrt{3}}$
⇒ $x^3=2+\sqrt{3}$
So, $\frac{1}{x^3}=\frac{1}{2+\sqrt{3}}×\frac{2-\sqrt{3}}{2-\sqrt{3}}=2-\sqrt{3}$
$\therefore x^3+\frac{1}{x^3}=2+\sqrt{3}+2-\sqrt{3}=4$
Hence, the correct answer is 4.
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 “”.