Binomial expansion of 3 terms

Write down the expansion of (1+x)^5 in ascending powers of x as far as the term in x^3 . Hence find the first four terms in the expansion of (1+x-x^2)^5 .

i need help for the second part of the question :smile:

Reply 1

krisshP

14

Original post by Sarah Lols

Write down the expansion of (1+x)^5 in ascending powers of x as far as the term in x^3 . Hence find the first four terms in the expansion of (1+x-x^2)^5 .

i need help for the second part of the question :smile:

As a guess, try replacing the x in the first expansion with x-x^2 :smile:

Reply 2

TenOfThem

18

Original post by Sarah Lols

Write down the expansion of (1+x)^5 in ascending powers of x as far as the term in x^3 . Hence find the first four terms in the expansion of (1+x-x^2)^5 .

i need help for the second part of the question :smile:

Use the first part

Just put