Advertisements
Advertisements
प्रश्न
Which term of the G.P.:
`-10, 5/sqrt(3), -5/6,....` is `-5/72`?
उत्तर
For the given G.P. :
First term, a = –10
Common ratio, r = `(5/sqrt(3))/(-10) = -1/(2sqrt(3))`
If `-5/72` is the nth term of the given G.P., then `-5/(72)` = arn – 1
`\implies -5/72 = -10 xx (1/(2sqrt(3)))^(n - 1)`
`\implies 1/144 = (1/(2sqrt(3)))^(n - 1)`
`\implies 1/(2 xx 2 xx 2 xx 2 xx sqrt(3) xx sqrt(3) xx sqrt(3) xx sqrt(3)) =(1/(2sqrt3))^(n - 1)`
`\implies (1/(2sqrt3))^4=(1/(2sqrt3))^("n"-1)`
`\implies` n – 1 = 4
`\implies` n = 4 + 1
`\implies` n = 5
APPEARS IN
संबंधित प्रश्न
Find, which of the following sequence from a G.P. :
9, 12, 16, 24, ................
Find the 9th term of the series :
1, 4, 16, 64, ...............
Find the G.P. whose first term is 64 and next term is 32.
The fourth term, the seventh term and the last term of a geometric progression are 10, 80 and 2560 respectively. Find its first term, common ratio and number of terms.
Find the third term from the end of the G.P.
`2/27, 2/9, 2/3, .........,162.`
Q 7
If a, b and c are in G.P., prove that : log a, log b and log c are in A.P.
If each term of a G.P. is raised to the power x, show that the resulting sequence is also a G.P.
Find the sum of G.P. :
0.3 + 0.03 + 0.003 + 0.0003 + ........... to 8 items.
Find the sum of G.P. :
`1 - 1/3 + 1/3^2 - 1/3^3 + .........` to n terms.
