SOLUTION: I am stuck on a math question and need help. The question is: Write out the expansion of (x+1)^6 using the Binomial Theorem. Any help would be greatly appreciated. Than

Algebra ->  Sequences-and-series -> SOLUTION: I am stuck on a math question and need help. The question is: Write out the expansion of (x+1)^6 using the Binomial Theorem. Any help would be greatly appreciated. Than      Log On


   



Question 253679: I am stuck on a math question and need help. The question is:
Write out the expansion of (x+1)^6 using the Binomial Theorem.

Any help would be greatly appreciated.
Thank you - Lori

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

%28x%2B1%29%5E6 Start with the given expression

To expand this, we're going to use binomial expansion. So let's look at Pascal's triangle:
1   

1   1   

1   2   1   

1   3   3   1   

1   4   6   4   1   

1   5   10   10   5   1   

1   6   15   20   15   6   1   




Looking at the row that starts with 1,6, etc, we can see that this row has the numbers:

1, 6, 15, 20, 15, 6, and 1

These numbers will be the coefficients of our expansion. So to expand %28x%2B1%29%5E6, simply follow this procedure:
Write the first coefficient. Multiply that coefficient with the first binomial term x and then the second binomial term 1. Repeat this until all of the coefficients have been written.

Once that has been done, add up the terms like this:


Notice how the coefficients are in front of each term.



However, we're not done yet.


Looking at the first term 1%28x%29%281%29, raise x to the 6th power and raise 1 to the 0th power.

Looking at the second term 6%28x%29%281%29 raise x to the 5th power and raise 1 to the 1st power.

Continue this until you reach the final term.


Notice how the exponents of x are stepping down and the exponents of 1 are stepping up.


So the fully expanded expression should now look like this:





Distribute the exponents


1%28x%5E6%29%2B6%28x%5E5%29%2B15%28x%5E4%29%2B20%28x%5E3%29%2B15%28x%5E2%29%2B6%28x%29%2B1 Multiply


x%5E6%2B6x%5E5%2B15x%5E4%2B20x%5E3%2B15x%5E2%2B6x%2B1 Multiply the terms with their coefficients


So %28x%2B1%29%5E6 expands and simplifies to x%5E6%2B6x%5E5%2B15x%5E4%2B20x%5E3%2B15x%5E2%2B6x%2B1.


In other words, %28x%2B1%29%5E6=x%5E6%2B6x%5E5%2B15x%5E4%2B20x%5E3%2B15x%5E2%2B6x%2B1