Thread: Series problem (again!)

Hi guys, so i was doing this one question and cant find a way through. It goes by like this :
What is the condition such that the series

1+[7/(3x+5)]+[7+(3x+5)^2].... is converge
hence show that the sum of the above series is 3x-5/3x-12

Originally Posted by nisbahmumtaz

1+[7/(3x+5)]+[7+(3x+5)^2].... is converge
hence show that the sum of the above series is 3x-5/3x-12

Could you write the series and the answer correctly? I suspect the answer is not .

My bad. Sorry. It's (3x-5)/(3x-12)

Originally Posted by nisbahmumtaz

Hi guys, so i was doing this one question and cant find a way through. It goes by like this :
What is the condition such that the series
1+[7/(3x+5)]+[7+(3x+5)^2].... is converge
hence show that the sum of the above series is 3x-5/3x-12

Is that + correct? Could it be
If not then it diverges.

And (using geometric progression).

Edit: added ^i to the formula.

Originally Posted by Plato

Is that + correct? Could it be
If not then it diverges.

Yikes. Darn it this iphone keyboard. Its supposed to be " / " not "+"

Originally Posted by nisbahmumtaz

Yikes. Darn it this iphone keyboard. Its supposed to be " / " not "+"

The see reply #5 for the correct answer.