Sum of Coefficients

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ddeyv

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The sum of the coefficients in the expansion: (x+2y+z)4(x+3y)5

I know the binomial expansion formula but it seems it wont work in a multinomial. Please provide me a solution and I will try to figure it out myself. Thank you!
 
ddeyv said:
The sum of the coefficients in the expansion: (x+2y+z)4(x+3y)5

I know the binomial expansion formula but it seems it wont work in a multinomial. Please provide me a solution and I will try to figure it out myself. Thank you!
Click to expand...
Have you tried to calculate "The sum of the coefficients in the binomial expansion"

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:


Please share your work/thoughts about this problem.
 
I do not know anything about binomial expansion when there are more than 1 variables and even of that form.
 
ddeyv said:
The sum of the coefficients in the expansion: (x+2y+z)4(x+3y)5

I know the binomial expansion formula but it seems it wont work in a multinomial. Please provide me a solution and I will try to figure it out myself. Thank you!
Click to expand...
Can you list the coefficients of expansion of (a + b)7? Can you calculate their sum?
 
sorry. i did not realize it does work for a multinomial. i was thinking the wrong formula which is finding the nth term of a binomial expansion.

(1+2+1)4(1+3)5

does this suffice?
 
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If you know the binomial formula for a sum of two terms then assume that you have two terms!!!!

For example (a+b+c)3 ( (a+b)+c )3 = (a+b)3+ 3(a+b)2c+ 3(a+b)c2+ c3 = ...
 
Jomo said:
If you know the binomial formula for a sum of two terms then assume that you have two terms!!!!

For example (a+b+c)3 ( (a+b)+c )3 = (a+b)3+ 3(a+b)2c+ 3(a+b)c2+ c3 = ...
Click to expand...
is my answer also considered correct?
 
ddeyv said:
sorry. i did not realize it does work for a multinomial. i was thinking the wrong formula which is finding the nth term of a binomial expansion.

(1+1+1)4(1+3)5

does this suffice?
Click to expand...
If this is your answer then I do not believe that you know (or at least did not use) the binomial formula.

Please use the binomial formula to expand (a+b)7 and then add the coefficients. Where are you getting the coefficients from? Is there a quicker why to get the sum?
 
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