Easy -1.8 This is a straightforward differentiation and substitution problem requiring only basic knowledge that d/dx(k/x) = -k/x². Students simply differentiate, substitute x=2 and gradient=-3, then solve for k. It's simpler than typical A-level questions as it involves a single-step differentiation of a basic function with immediate substitution.
1 A curve has equation $y = \frac { k } { x }$. Given that the gradient of the curve is - 3 when $x = 2$, find the value of the constant $k$.
\hfill \mbox{\textit{CAIE P1 2006 Q1 [3]}}