26 Views

Question : If $x-\frac{1}{x}=-6$, what will be the value of $x^5-\frac{1}{x^5}?$

Option 1: –8898

Option 2: –8896

Option 3: –8886

Option 4: –8892


Team Careers360 23rd Jan, 2024
Answer (1)
Team Careers360 24th Jan, 2024

Correct Answer: –8886


Solution : Given: $x-\frac{1}{x}=-6$ ----------------(equation1)
Squaring both sides of equation 1, we get:
⇒ $x^2+\frac{1}{x^2}-2=(-6)^2$
⇒ $x^2+\frac{1}{x^2}=38$
Cubing both sides of equation 1, we get:
⇒ $x^3-\frac{1}{x^3}-3×x×\frac{1}{x}(x-\frac{1}{x})=(-6)^3$
⇒ $x^3-\frac{1}{x^3}=-216+3×(-6)$
⇒ $x^3-\frac{1}{x^3}=-234$
Now, $(x^2+\frac{1}{x^2})(x^3-\frac{1}{x^3})=38×(-234)$
⇒ $(x^5-\frac{1}{x^5})+(x-\frac{1}{x})=(-8892)$
⇒ $(x^5-\frac{1}{x^5})+(-6)=(-8892)$
$\therefore(x^5-\frac{1}{x^5})= -8886$
Hence, the correct answer is –8886.

SSC CGL Complete Guide

Candidates can download this ebook to know all about SSC CGL.

Download EBook

Know More About

Related Questions

TOEFL ® Registrations 2024
Apply
Accepted by more than 11,000 universities in over 150 countries worldwide
Manipal Online M.Com Admissions
Apply
Apply for Online M.Com from Manipal University
GRE ® Registrations 2024
Apply
Apply for GRE® Test now & save 10% with ApplyShop Gift Card | World's most used Admission Test for Graduate & Professional Schools
View All Application Forms

Download the Careers360 App on your Android phone

Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile

150M+ Students
30,000+ Colleges
500+ Exams
1500+ E-books