Find the ratio of the coefficients of the 4th and 6th terms in the expansion of (1 + 2x)^16

1 answer

You had a similar question like this before
http://www.jiskha.com/display.cgi?id=1375847416

anyway...

(1+2x)^16

= 1 + C(16,1) (2x)^1 + C(16,2) (2x)^2 + ...

term 4 = C(16,3) (2x)^3 = 4480x^3
term 6 = C(16,5) (2x)^5 = 139776x^5

4480 : 139776 = 5:156