wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Let ai, i=1,2,,n be an A.P. If a7=9, then the value of common difference of the A.P. such that a1a2a7 is minimum, is

A
1120
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
3320
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
2
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
3
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B 3320
a7=a1+6d
a2=a1+d
a1a2a7=a1(a1+d)9 =9a1(a1+9a16)
=32(5a21+9a1)

Let f(a1)=32(5a21+9a1)
f(a1)=32(10a1+9)
a1=910 is the point of minima of f.
d=9+9106=3320

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Arithmetic Progression
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon