Question

Find the 7th term of (x+y)^8

Answer 1

By the binomial theorem, we have


`(x+y)^8=\displaystyle\sum_(k=0)^8\binom8kx^(8-k)y^k`

where
`\dbinom8k=(8!)/(k!(8-k)!)`. The 7th term occurs when
`k=6`, which gives


`\dbinom86x^(8-6)y^6=28x^2y^6`