The equation of a curve is \(y = x \ln(8 - x)\). The gradient of the curve is equal to 1 at only one point, when \(x = a\).
(i) Show that \(a\) satisfies the equation \(x = 8 - \frac{8}{\ln(8 - x)}\).
(ii) Verify by calculation that \(a\) lies between 2.9 and 3.1.
(iii) Use an iterative formula based on the equation in part (i) to determine \(a\) correct to 2 decimal places. Give the result of each iteration to 4 decimal places.
The curve with equation \(y = x^2 \cos \frac{1}{2}x\) has a stationary point at \(x = p\) in the interval \(0 < x < \pi\).
The diagram shows the curve \(y = \csc x\) for \(0 < x < \pi\) and part of the curve \(y = e^{-x}\). When \(x = a\), the tangents to the curves are parallel.
(i) By differentiating \(\frac{1}{\sin x}\), show that if \(y = \csc x\) then \(\frac{dy}{dx} = -\csc x \cot x\). [3]
(ii) By equating the gradients of the curves at \(x = a\), show that \(a = \arctan \left( \frac{e^a}{\sin a} \right)\). [2]
(iii) Verify by calculation that \(a\) lies between 1 and 1.5. [2]
(iv) Use an iterative formula based on the equation in part (ii) to determine \(a\) correct to 3 decimal places. Give the result of each iteration to 5 decimal places. [3]
A curve has parametric equations
\(x = t^2 + 3t + 1, \quad y = t^4 + 1.\)
The point \(P\) on the curve has parameter \(p\). It is given that the gradient of the curve at \(P\) is 4.
The diagram shows part of the curve with parametric equations
\(x = 2 \ln(t + 2)\), \(y = t^3 + 2t + 3\).