CAIE P1 2015 November — Question 9

Exam BoardCAIE
ModuleP1 (Pure Mathematics 1)
Year2015
SessionNovember
TopicConnected Rates of Change

9 A curve passes through the point \(A ( 4,6 )\) and is such that \(\frac { \mathrm { d } y } { \mathrm {~d} x } = 1 + 2 x ^ { - \frac { 1 } { 2 } }\). A point \(P\) is moving along the curve in such a way that the \(x\)-coordinate of \(P\) is increasing at a constant rate of 3 units per minute.
  1. Find the rate at which the \(y\)-coordinate of \(P\) is increasing when \(P\) is at \(A\).
  2. Find the equation of the curve.
  3. The tangent to the curve at \(A\) crosses the \(x\)-axis at \(B\) and the normal to the curve at \(A\) crosses the \(x\)-axis at \(C\). Find the area of triangle \(A B C\).