Question

(a + b) ^11
which term is independent of a ?
write the cofficent of that term?

Answer 1

Best Answer
well for nCr, nCr is the same as nC(n-r)

So for a^2b^9 we have 11C2 / 11C9 (i'd probably write it as 11C2 since the a powers are expanding) which is the same as 11!/( 2! * 9!) = 55

a^11 will be 11C0 / 11C11 which is just 1

a^6b^5 is either 11C6 / 11C5 (both the same) which is the same as 462