emergency

[fatemeh8989]

hi
we know that (1+x+x^2+x^3+...) = 1/(1-x) ;
I need to know is there any sequence of sentences like above to produce: 1/(1-2x) ? "emergency"

 

[pka]

hi
we know that (1+x+x^2+x^3+...) = 1/(1-x) ;
I need to know is there any sequence of sentences like above to produce: 1/(1-2x) ? "emergency"

\(\displaystyle !+2x+4x^2+8x^3+\cdots=\dfrac{1}{1-2x}\) as long as \(\displaystyle |x|<0.5\).

 

[Deleted member 4993]

hi
we know that (1+x+x^2+x^3+...) = 1/(1-x) ;
I need to know is there any sequence of sentences like above to produce: 1/(1-2x) ? "emergency"

substtitute

u = 2x

find the series ....

substitute back

2x = u

done....

 

[fatemeh8989]

Thank you every one. they were helpful.