Find $f ' (x)$.

The gradient of the curve at point A is 35.

Find the x-coordinate of point A.

$f'(x) = 3 + \frac{4}{{{x^3}}}$     (A1)(A1)(A1)     (C3)

Notes: Award (A1) for 3, (A1) for + 4 and (A1) for $\frac{1}{{{x^3}}}$  or $x^{-3}$. Award at most (A1)(A1)(A0) if additional terms are seen.

$3 + \frac{4}{{{x^3}}} = 35$     (M1)

Note: Award (M1) for equating their derivative to 35 only if the derivative is not a constant.

${x^3} = \frac{1}{8}$     (A1)(ft)

$\frac{1}{2}(0.5)$     (A1)(ft)     (C3)