Question

The coefficients in the expansion of (x + y)4

Answer 1

Answer:

A

Step-by-step explanation:

Notice:  The literal factors are all the combinations of a and b where the sum of the exponents is 4:  a4,  a3b,  a2b2,  ab3,  b4.

The degree of each term is 4.

The first term is actually a4b0, which is a4 · 1.

Thus to "expand" (a + b)5, we would anticipate the following terms, in which the sum of all the exponents is 5:

(a + b)5 =  ? a5 +  ? a4b +  ? a3b2 +  ? a2b3 +  ? ab4 +  ? b5

The question is, What are the coefficients?

They are called the binomial coefficients.  In the expansion of

(a + b)4, the binomial coefficients are

1  4  6  4  1