- #1
Jef123
- 29
- 0
I'm having a hard time seeing how spivak derived this formula...
"6. The formula for 12+...+n2 may be derived as follows...
(k+1)3 - k3 = 3k2+3k+1 where k=1,...,n
Therefore, (n+1)3 - n3 = 3n2+3n+1
But this is where I am confused...He then presents this,
(n+1)3 - 1 = 3[12 +...n2]+3[1+...+n]+n
Where did the "1" come from on the left hand side of the equation? And where did the "n" come from at the far right hand side of the equation?
On a side note, I am having a lot of difficulty going through this text myself, mainly due to the fact that I feel a little lost with how to do proofs. I have done a calculus course before, but this text is much more difficult. Does anyone suppose that as I continue to go through the text that I will develop a better sense of how to do proofs and feel more comfortable with understanding this material? Any suggestions would be great
"6. The formula for 12+...+n2 may be derived as follows...
(k+1)3 - k3 = 3k2+3k+1 where k=1,...,n
Therefore, (n+1)3 - n3 = 3n2+3n+1
But this is where I am confused...He then presents this,
(n+1)3 - 1 = 3[12 +...n2]+3[1+...+n]+n
Where did the "1" come from on the left hand side of the equation? And where did the "n" come from at the far right hand side of the equation?
On a side note, I am having a lot of difficulty going through this text myself, mainly due to the fact that I feel a little lost with how to do proofs. I have done a calculus course before, but this text is much more difficult. Does anyone suppose that as I continue to go through the text that I will develop a better sense of how to do proofs and feel more comfortable with understanding this material? Any suggestions would be great