WAEC - Further Mathematics (2019 - No. 28)
Find the coefficient of the third term in the binomial expansion of [2x + \(\frac{3y}{4}\)]\(^3\) in descending powers of x.
\(\frac{27}{64}\)y\(^2\)
\(\frac{27}{8}\)y\(^2\)
8y\(^2\)
9y\(^2\)
คำอธิบาย
(2x + \(\frac{3y}{4}\))\(^3\)
= 3(2x) (\(\frac{3y}{4}\))\(^2\)
= \(\frac{27}{8}\)y\(^2\)