OCR C1 2005 January — Question 9

Exam BoardOCR
ModuleC1 (Core Mathematics 1)
Year2005
SessionJanuary
TopicDifferentiation Applications
TypeFind stationary points

9
  1. Find the gradient of the curve \(y = 2 x ^ { 2 }\) at the point where \(x = 3\).
  2. At a point \(A\) on the curve \(y = 2 x ^ { 2 }\), the gradient of the normal is \(\frac { 1 } { 8 }\). Find the coordinates of \(A\). Points \(P _ { 1 } \left( 1 , y _ { 1 } \right) , P _ { 2 } \left( 1.01 , y _ { 2 } \right)\) and \(P _ { 3 } \left( 1.1 , y _ { 3 } \right)\) lie on the curve \(y = k x ^ { 2 }\). The gradient of the chord \(P _ { 1 } P _ { 3 }\) is 6.3 and the gradient of the chord \(P _ { 1 } P _ { 2 }\) is 6.03.
  3. What do these results suggest about the gradient of the tangent to the curve \(y = k x ^ { 2 }\) at \(P _ { 1 }\) ?
  4. Deduce the value of \(k\).