







1+2+4+8....= 1 
20120402 

From Andy: In this minutephysics video, it's claimed that 1+2+4+8....= 1
Is this true, and if so, how?
< href="http://www.youtube.com/watch?v=kIq5CZlg8Rg">http://www.youtube.com/watch?v=kIq5CZlg8Rg Answered by Robert Dawson. 





1/1+1/2+1/3... 
20100331 

From Mohd: you explained the way of getting the summation of 100 series numbers
but what is the summation of the numbers 1/1+1/2+1/3+1/4+1/5.............................+1/100 Answered by Robert Dawson. 





Summation Notation 
20091228 

From MANDIRA: I want to get the formula for expressing one number by summation of consucutive numbers . Answered by Janice Cotcher. 





Total payments for a loan 
20071011 

From Robin: A person is going to arrange a loan at 3 mill. he will pay 150000 back each year , so it
take 20 yrs. to finish. In addition he pays 5% interest of what is leaft each year.
How do I find the sumfunction which shows the total sum he have payed? Answered by Stephen La Rocque. 





The odd numbers from 30 to 80 
20060921 

From Kieran: If you added all the odd numbers from 30 to 80, would the answer be even or odd? Explain.
I think it would be odd because I used this equation:
(30 x 5)+(40 x 5)+(50 x 5)+(60 x 5)+(70 x 5)+(25 x 5)=1325
I used the numbers for each set of ten 30 to 80 times 5 and the amount of the endings1,3,5,7,9 added, times 5. Is that right? Answered by Penny Nom. 





Proving a summation formula by induction 
20060419 

From Sharon: Prove by induction that the sum of all values 2^i from i=1 to n equals 2^(n+1)  2 for n > 1. Answered by Stephen La Rocque. 





1+3+5+...+(2n+1) 
20040910 

From Emma: Prove that 1+3+5+...+(2n+1)= (n+1)^{2} Answered by Penny Nom. 

