Review question

# Can we find the minimum value of $x^2+2/x$ for $x$ positive? Add to your resource collection Remove from your resource collection Add notes to this resource View your notes for this resource

Ref: R5640

## Question

1. Find and simplify the coefficient of $x^7$ in the binomial expansion of $\left( x^2 + \dfrac{2}{x} \right)^8$.

2. Calculate the minimum value of $x^2 + \dfrac{2}{x}$ for positive values of $x$.

3. Given that $y = \left( x^2 + \dfrac{2}{x} \right)^8$, find the value of $\dfrac{dy}{dx}$ when $x = -1$.