Mathematics 9709 · AS & A Level · Series

Series — practice question

In $(3 + x)^5$, the coefficient of $x^4$ is the same as the coefficient of $x^2$ in $(2x + \frac{a}{x})^6$.

(main)[4]

Find the value for the positive constant $a$.

Worked solution & mark scheme

This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “States that the coefficient of $x^4$ is $15$.” …