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pappueshwar
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pappueshwar wrote:A sequence of numbers (geometric sequence) is given by the expression:
If the sequence begins with n = 1, what are the first two terms for which?
options:
A ) g10, g11
B)g11, g12
C) g12, g13
D) g13, g14
E) g14, g15
OA IS D
When n is even the expression is positive and when n is odd the expression is negative.
Also we need to remember that 2^10=1024
|g1-g2|=|5(-1/2)-5(1/4)|=15/2^2 which is close to 2^4/2^2.
|g2-g3|=|5(1/4)-5(-1/8)|=15/2^3 which is close to 2^4/2^2
So in order for given expression to be < 1/1000 which is close to 1/2^10 or < 2^4/2^14.
|g13-g14| would be close to 2^4/2^14. Hence D
