A Anemori Jan 2010 142 0 May 11, 2010 #1 is the right equation for S_n= 1+x+x^2+x^3+...+x^(n-1) ? \(\displaystyle \sum_x^{\infty} \frac{1-x^(n-1)}{1-x} \) the numerator is 1-x^(n-1) is the right equation? thanks!

is the right equation for S_n= 1+x+x^2+x^3+...+x^(n-1) ? \(\displaystyle \sum_x^{\infty} \frac{1-x^(n-1)}{1-x} \) the numerator is 1-x^(n-1) is the right equation? thanks!

C choovuck Aug 2008 74 23 May 11, 2010 #2 you should edit your post cause it's completely confusing. if you're asking about what is the sum of 1+x+x^2+...+x^(n-1) equal to, then the answer is (1-x^n)/(1-x)

you should edit your post cause it's completely confusing. if you're asking about what is the sum of 1+x+x^2+...+x^(n-1) equal to, then the answer is (1-x^n)/(1-x)

A Anemori Jan 2010 142 0 May 11, 2010 #3 choovuck said: you should edit your post cause it's completely confusing. if you're asking about what is the sum of 1+x+x^2+...+x^(n-1) equal to, then the answer is (1-x^n)/(1-x) Click to expand... I tried to fix it but the exponent of n-1 always messed up. Thanks for the help, I wasnt sure if i did it right... Can you give me example using this (1-x^n/1-x) thanks...

choovuck said: you should edit your post cause it's completely confusing. if you're asking about what is the sum of 1+x+x^2+...+x^(n-1) equal to, then the answer is (1-x^n)/(1-x) Click to expand... I tried to fix it but the exponent of n-1 always messed up. Thanks for the help, I wasnt sure if i did it right... Can you give me example using this (1-x^n/1-x) thanks...

Prove It MHF Helper Aug 2008 12,883 4,999 May 11, 2010 #4 Anemori said: I tried to fix it but the exponent of n-1 always messed up. Thanks for the help, I wasnt sure if i did it right... Can you give me example using this (1-x^n/1-x) thanks... Click to expand... Write your exponents inside {}. So you need to write 1 - x^{n - 1} to get \(\displaystyle 1 - x^{n - 1}\).

Anemori said: I tried to fix it but the exponent of n-1 always messed up. Thanks for the help, I wasnt sure if i did it right... Can you give me example using this (1-x^n/1-x) thanks... Click to expand... Write your exponents inside {}. So you need to write 1 - x^{n - 1} to get \(\displaystyle 1 - x^{n - 1}\).

A Anemori Jan 2010 142 0 May 11, 2010 #5 Prove It said: Write your exponents inside {}. So you need to write 1 - x^{n - 1} to get \(\displaystyle 1 - x^{n - 1}\). Click to expand... \(\displaystyle S_n= 1+x+x^2+x^3+...+x^{n-1} ? \) = \(\displaystyle \sum_{x=\infty}^{n-1} a_1 \frac{1-x^n}{1-x} \) right? im looking for \(\displaystyle S_7 \) using the the formula. I don't know how to start because I don't have variables for x.

Prove It said: Write your exponents inside {}. So you need to write 1 - x^{n - 1} to get \(\displaystyle 1 - x^{n - 1}\). Click to expand... \(\displaystyle S_n= 1+x+x^2+x^3+...+x^{n-1} ? \) = \(\displaystyle \sum_{x=\infty}^{n-1} a_1 \frac{1-x^n}{1-x} \) right? im looking for \(\displaystyle S_7 \) using the the formula. I don't know how to start because I don't have variables for x.