Question

What is the coeffieent of (x^4)(y^4) in the expansion of (x+y)^8

Answer 1

ANSWER

The coefficient is 70.

EXPLANATION

The given binomial expression is

$(x+y)^8$

The specific term of a binomial expansion can be determined using the formula,

$T_{r+1}= nC_ra^{n-r}b^r$
where

$n=8,r=4,a=x,b=y$

We substitute these values into the formula to get,

$T_{4+1}= 8C_4x^{8-4}y^4$

We simplify to get,

$T_{5}= 70x^{4}y^4$

Hence the coefficient is 70.