the first three terms in the expansion of (1+ay)to the power of n are 1, 12y, and 68y to the power of 2.

Question

Evaluate a and n. us the factor that (1+ay)©ú= 1+nay+n(n-1) (ay)2+¡¦
2

Answer 1

Your second sentence/equation has many errors. You probably meant to write
" USE the FACT that
(1+ay)^n = 1 + nay +n(n-1)(ay)^2)/2 + ... "
This is called a Taylor series.

In this case, by comparing terms in an expansion in a power series of ay,
you may be able to solve for both a and n