How did this conversion took place ?

  • Thread starter Thread starter Sumedh
  • Start date Start date
AI Thread Summary
The discussion centers on the derivation of a summation formula from an initial expression, specifically transitioning from 6(2)^(n-2) + 1 to 6(2)^(n-1) + n + 2. Participants clarify that the two expressions are not equivalent and emphasize that they are expressions rather than equations, lacking an equality sign. A specific example using n = 2 demonstrates that the values produced by both expressions do not match, indicating a misunderstanding in the summation process. There is also a request for clarification on the notation and potential missing symbols. Ultimately, the conversation highlights the need for accurate mathematical representation in problem-solving.
Sumedh
Messages
61
Reaction score
0

Homework Statement


6(2)^(n-2) +1

then summation of above equation will be
6(2)^(n-1) + n + 2

can you please tell me how this equaton came from the first equation?

The Attempt at a Solution



the later formula is correct summation of the former

because it may look that the summation is
6(2)^(n-1) +n - 3

but by putting values of n-
6(2)^(n-1) +n - 3 is incorrect

please help as how the topmost formula gives the second formula
 
Last edited:
Physics news on Phys.org
Sumedh said:

Homework Statement


6(2)^(n-2) +1

then summation of above equation will be
6(2)^(n-1) + n + 2

can you please tell me how this equaton came from the first equation?
It doesn't. First off, these aren't equations - they are expressions. An equation is a statement that two expressions are equal, and always has an = symbol in it.

Starting from your first expression,
6\cdot2n-2 + 1 = 6\cdot2n-1\cdot(1/2) + 1 = 3\cdot2n-1 + 1

To show that your two expressions above aren't identically equal, let n = 2. Then 6\cdot2n-2 + 1 = 6 * 1 + 1 = 7.

And 6\cdot2n-1 + n + 2 = 6* 2 + 2 + 2 = 16.

Sumedh said:

The Attempt at a Solution



the later formula is correct summation of the former

because it may look that the summation is
6(2)^(n-1) +n - 3

but by putting values of n-
6(2)^(n-1) +n - 3 is incorrect

please help as how the topmost formula gives the second formula
 
I'm not sure what these expressions (and these are expressions, not equation) are. Are there any symbols missing? Can you attach an image, or retype using LaTeX?
 
I get a "page is unavailable" error.
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks

Similar threads

Replies
6
Views
2K
Replies
12
Views
3K
Replies
9
Views
3K
Replies
8
Views
2K
Replies
33
Views
3K
Back
Top