SPS SPS SM 2020 June — Question 10 8 marks

Exam BoardSPS
ModuleSPS SM (SPS SM)
Year2020
SessionJune
Marks8
TopicTangents, normals and gradients
TypeFind tangent at given point (polynomial/algebraic)
DifficultyModerate -0.3 Part (a) requires solving 3x - 2√x = 8x - 16 by substituting u = √x to get a quadratic, which is a standard technique but involves multiple algebraic steps. Part (b) is straightforward identification of inequalities from a diagram. Overall slightly easier than average due to routine algebraic manipulation with no novel problem-solving required.
Spec1.02f Solve quadratic equations: including in a function of unknown1.02i Represent inequalities: graphically on coordinate plane1.02q Use intersection points: of graphs to solve equations

\includegraphics{figure_3} Figure 3 shows a sketch of the curve \(C\) with equation \(y = 3x - 2\sqrt{x}\), \(x \geqslant 0\) and the line \(l\) with equation \(y = 8x - 16\) The line cuts the curve at point \(A\) as shown in Figure 3.
  1. Using algebra, find the \(x\) coordinate of point \(A\). [5]
  2. \includegraphics{figure_4} The region \(R\) is shown unshaded in Figure 4. Identify the inequalities that define \(R\). [3]

\includegraphics{figure_3}

Figure 3 shows a sketch of the curve $C$ with equation $y = 3x - 2\sqrt{x}$, $x \geqslant 0$ and the line $l$ with equation $y = 8x - 16$

The line cuts the curve at point $A$ as shown in Figure 3.

\begin{enumerate}[label=(\alph*)]
\item Using algebra, find the $x$ coordinate of point $A$. [5]

\item \includegraphics{figure_4}

The region $R$ is shown unshaded in Figure 4. Identify the inequalities that define $R$. [3]
\end{enumerate}

\hfill \mbox{\textit{SPS SPS SM 2020 Q10 [8]}}