CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

If x+1x=3, calculate x2+1x2, x3+1x3 and x4+1x4

A
8,18,47
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
7,19,47
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
7,18,49
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
7,18,47
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct option is C 7,18,47
Given,

x+1x=3

squaring on both sides, we get,

x2+1x2+2=9

x2+1x2=7..........(i)

squaring on both sides, we get,

x4+1x4+2=49

x4+1x4=47..........(iii)

Taking cube on both the side

(x+1x)3=x3+1x3+3(x+1x).............(a+b)3=a3+3ab(a+b)+b3

33=x3+1x3+3(3)

x3+1x3=333(3)=18..........(ii)

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
(x+y)^3
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon