Edexcel FP2 — Question 6 15 marks

Exam BoardEdexcel
ModuleFP2 (Further Pure Mathematics 2)
Marks15
PaperDownload PDF ↗
TopicSecond order differential equations
TypeParticular solution with initial conditions
DifficultyStandard +0.8 This is a standard second-order linear ODE with constant coefficients and a non-homogeneous term, requiring complementary function (repeated root case), particular integral (trying x = A cos 3t + B sin 3t), and applying initial conditions. Part (c) adds a numerical/graphical element requiring understanding of long-term behavior. While methodical, it's more demanding than typical A-level pure maths due to the algebraic manipulation and being Further Maths content, but follows standard FP2 procedures without requiring novel insight.
Spec4.10e Second order non-homogeneous: complementary + particular integral

\includegraphics{figure_1} The differential equation $$\frac{d^2 x}{dt^2} + 6 \frac{dx}{dt} + 9x = \cos 3t, \quad t \geq 0,$$ describes the motion of a particle along the \(x\)-axis.
  1. Find the general solution of this differential equation. [8]
  2. Find the particular solution of this differential equation for which, at \(t = 0\), \(x = \frac{1}{2}\) and \(\frac{dx}{dt} = 0\). [5]
On the graph of the particular solution defined in part (b), the first turning point for \(T > 30\) is the point \(A\).
  1. Find approximate values for the coordinates of \(A\). [2]

\includegraphics{figure_1}

The differential equation
$$\frac{d^2 x}{dt^2} + 6 \frac{dx}{dt} + 9x = \cos 3t, \quad t \geq 0,$$
describes the motion of a particle along the $x$-axis.

\begin{enumerate}[label=(\alph*)]
\item Find the general solution of this differential equation. [8]
\item Find the particular solution of this differential equation for which, at $t = 0$, $x = \frac{1}{2}$ and $\frac{dx}{dt} = 0$. [5]
\end{enumerate}

On the graph of the particular solution defined in part (b), the first turning point for $T > 30$ is the point $A$.

\begin{enumerate}[label=(\alph*)]
\setcounter{enumi}{2}
\item Find approximate values for the coordinates of $A$. [2]
\end{enumerate}

\hfill \mbox{\textit{Edexcel FP2  Q6 [15]}}