BG wrote:

may be i am wrong but i multiplied the left part of the inequality with (1-x) and got 1-x+x-x^2+x^2-x^3+x^3-x^4+x^4-x^5>1 wich simplifies to -x^5>0 or x^5<0

now think that it should be A)

you can do this if 1-x is greater than 1 or smaller than -1

Otherwise you've to flip the inequality sign

In this case, try 1/2 as X -> 31/16

is less than 1/0.5=2 (answ=NO)

try 2 as X -> 1+2...

is greater than 1/2=0.5 (ANSW=YES)

Not sufficient

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