coefficient question (1 Viewer)

[user18181818]

help please - answer is C

 

[synthesisFR]

help please - answer is C
View attachment 40168

if u sub in n=50 to get the expression thing
theres 51 terms in each bracket, and each of them multiplies with one term from the other bracket to get x^50 right
so then if u expand out and just list the coefficients of x^50 u get
1 + 2 + 3 + ... + 50 + 51
which is an arithmetic series
so 51/2 ( 2x1 + 50) = 1326
if that makes sense?

ps which paper is this frrom

 

[Unovan]

nice question

 

[user18181818]

if u sub in n=50 to get the expression thing
theres 51 terms in each bracket, and each of them multiplies with one term from the other bracket to get x^50 right
so then if u expand out and just list the coefficients of x^50 u get
1 + 2 + 3 + ... + 50 + 51
which is an arithmetic series
so 51/2 ( 2x1 + 50) = 1326
if that makes sense?

ps which paper is this frrom

OH makes sense tysm
its from normo 2023