if the 10 th term of a G. P. is 9 th and 4 th term is4, then what is its7 th term??
Answers
Answered by
1
Answer:
Let the first term and common ratio of the given G.P be a and respectively.
T10 = ar9 = 9 ––––––(1)
T4 = ar³ = 4 —————(2)
T10/T4 = ar9/ar³= 9/4
r6 = 9/4
(r³)² = 9/4
r³ = 3/2
from (1) ar9 = 9
a(r³) = 9
Substituting the value of r³ from (iii) we get
a(3/2)³ = 9
a = 9×8/27 = 8/3
T7 = ar6 = 8/3 × 9/4 =6
I hope this is helps you.
Answered by
0
Answer:
be the first term of GP with common ratio r.
The nth term, an = arn-1
10th term, ar9 = 9…(i)
4th term, ar3 = 4…(ii)
Multiply (i) and (ii)
ar9ar3 = 36
a2r12 = 36
(ar6)2 = 36
Taking square root
ar6 = 6
So 7th term = ar6 = 6
Hence option (1) is the answer
Step-by-step explanation:
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