A curve CCC has equation
y=2x3−15x+kx,x>0 y = 2x^3 - 15x + \frac{k}{x}, \quad x > 0 y=2x3−15x+xk,x>0where kkk is a constant. The point PPP with xxx-coordinate 111 lies on CCC. Given that PPP is a stationary point of CCC:
show that k=−9k = -9k=−9.
Determine the nature of the stationary point at PPP, justifying your answer.
The curve CCC has a second stationary point.
Using algebra, find the xxx-coordinate of this second stationary point.
115 exam-style questions on CCEA A Level Maths 1.6 Differentiation, covering 1.6.1 Differentiation, 1.6.2 Differentiation, 1.6.3 Differentiation, 1.6.4 Differentiation, 1.6.5 Differentiation, 1.6.6 Differentiation, and 1.6.7 Differentiation. Each one has a worked solution and a mark scheme showing where the marks go.