Is 1+x+x^2+x^3+x^4<1/(1-x)?

1) x>0

2) x<1

* A solution will be posted in two days.

## Is 1+x+x^2+x^3+x^4<1/(1-x)? 1) x>0 2) x<1 * A so

##### This topic has expert replies

- [email protected] Revolution
- Elite Legendary Member
**Posts:**3991**Joined:**24 Jul 2015**Location:**Las Vegas, USA**Thanked**: 19 times**Followed by:**36 members

**Math Revolution**

**The World's Most "Complete" GMAT Math Course!**

Score an excellent Q49-51 just like 70% of our students.

[Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions.

[Course] Starting

**$79**for on-demand and

**$60**for tutoring per hour and

**$390**only for Live Online.

Email to : [email protected]

- [email protected] Revolution
- Elite Legendary Member
**Posts:**3991**Joined:**24 Jul 2015**Location:**Las Vegas, USA**Thanked**: 19 times**Followed by:**36 members

Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

Is 1+x+x^2+x^3+x^4<1/(1-x)?

1) x>0

2) x<1

The question is (1-x^5)/(1-x)<1/(1-x)? and -x^5/(1-x)<0?, x^5/(x-1)<0? is derived when delete 1/(1-x) from the both equations of 1/(1-x)-x^5/(1-x)<1/(1-x)?. When you multiply (x-1)^2 to the both equations, x^5(x-1)<0? is derived. Divide it with x^4 and it becomes x(x-1)<0?. That is, 0<x<1? is derived, which makes C the answer.

Is 1+x+x^2+x^3+x^4<1/(1-x)?

1) x>0

2) x<1

The question is (1-x^5)/(1-x)<1/(1-x)? and -x^5/(1-x)<0?, x^5/(x-1)<0? is derived when delete 1/(1-x) from the both equations of 1/(1-x)-x^5/(1-x)<1/(1-x)?. When you multiply (x-1)^2 to the both equations, x^5(x-1)<0? is derived. Divide it with x^4 and it becomes x(x-1)<0?. That is, 0<x<1? is derived, which makes C the answer.

**Math Revolution**

**The World's Most "Complete" GMAT Math Course!**

Score an excellent Q49-51 just like 70% of our students.

[Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions.

[Course] Starting

**$79**for on-demand and

**$60**for tutoring per hour and

**$390**only for Live Online.

Email to : [email protected]