Question

Find the (2n)th term of the G.P. \(-\frac{ 1 }{ 2 }\), 1, -2, 4 ...
A. \(2^{2n}\)
B. \(-2^{2n}\)
C. \(-2^{2n-3}\)
D. \(2^{2n-2}\)
E. \(-2^{2n-2}\)

Answer 1

@ganeshie8

Answer 2

\(\large -\frac{1}{2}, 1, -2, 4, ..... \)

Answer 3

...............?

Answer 4

find the common ratio r

Answer 5

r = 4/-2 = -2

Answer 6

i know

Answer 7

good:) , use nth term formula

Answer 8

(-1/2) / [1-(-2)] = -1/6 ??

Answer 9

\( a_n = a_1 r^{n-1}\)

Answer 10

n = 2n
r = -2

Answer 11

plugin

Answer 12

oopsssss

Answer 13

\(a_{2n} = -\frac{1}{2} (-2)^{2n-1}\)

Answer 14

(-1/2) * (-2)^(2n-1)

Answer 15

ok...

Answer 16

since 2n-1 is odd, that gives - sign

Answer 17

\(a_{2n} = \frac{1}{2} (2)^{2n-1}\)

= \(2^{2n-2}\)

Answer 18

oic...

Answer 19

- and - cancelled out

Answer 20

oh, i know now

Answer 21

good :)