Edexcel P2 2021 January — Question 7 6 marks

Exam BoardEdexcel
ModuleP2 (Pure Mathematics 2)
Year2021
SessionJanuary
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicNumerical integration
TypeComplete table then apply trapezium rule
DifficultyModerate -0.3 This is a straightforward application of the trapezium rule with 5 ordinates. Part (a) requires simple substitution into a given formula, and part (b) is a standard trapezium rule calculation with all values provided or easily computed. The context is applied but the mathematics is routine P2 content with no conceptual challenges.
Spec1.09f Trapezium rule: numerical integration

7. Figure 1 Solar panels are installed on the roof of a building. The power, \(P\), produced on a particular day, in kW , can be modelled by the equation $$P = 0.95 + 2 ^ { t - 12 } + 2 ^ { 12 - t } - ( t - 12 ) ^ { 2 } \quad 8.5 \leqslant t \leqslant 15.2$$ where \(t\) is the time in hours after midnight. The graph of \(P\) against \(t\) is shown in Figure 1. A table of values of \(t\) and \(P\) is shown below, with the values of \(P\) given to 4 significant figures where appropriate.
Time, \(t\)
(hours)
1010.51111.512
Power, \(P\)
(kW)
1.8822.452.95
  1. Use the given equation to complete the table, giving the values of \(P\) to 4 significant figures where appropriate. The amount of energy, in kWh , produced between 10:00 and 12:00 can be found by calculating the area of region \(R\), shown shaded in Figure 1.
  2. Use the trapezium rule, with all the values of \(P\) in the completed table, to find an estimate for the amount of energy produced between 10:00 and 12:00. Give your answer to 2 decimal places.
    7. \includegraphics[max width=\textwidth, alt={}, center]{52c90d0e-a5e4-45fa-95a4-9523287e7588-20_769_1038_116_450}

Question 7:
Part (a):
AnswerMarks Guidance
Answer/WorkingMark Guidance
\((t=10, P=)\ 1.2\) or \(\frac{6}{5}\)B1 Allow 1.200. May be seen in table or working for part (b)
\((t=11.5, P=)\ 2.821\)B1 awrt 2.821. May be seen in table or working for part (b)
Part (b):
AnswerMarks Guidance
Answer/WorkingMark Guidance
\(h = 0.5\)B1 Seen or implied
\(E \approx \left(\frac{1}{2} \times \frac{1}{2}\right)\left[1.2 + 2.95 + 2(1.882 + 2.45 + 2.821)\right]\)M1 Correct bracket structure: first \(P\) value plus last \(P\) value, inner bracket multiplied by 2 containing remaining \(P\) values. Allow recovery of invisible brackets. M0 if \(t\) values used instead of \(P\) values
A1ftCorrect bracket \([\ldots]\) following through their values from (a)
\(E \approx 4.61\) (kWh)A1 cao, must be to 2 d.p. (exact answer via integration is 4.643439737)
## Question 7:

### Part (a):

| Answer/Working | Mark | Guidance |
|---|---|---|
| $(t=10, P=)\ 1.2$ or $\frac{6}{5}$ | B1 | Allow 1.200. May be seen in table or working for part (b) |
| $(t=11.5, P=)\ 2.821$ | B1 | awrt 2.821. May be seen in table or working for part (b) |

### Part (b):

| Answer/Working | Mark | Guidance |
|---|---|---|
| $h = 0.5$ | B1 | Seen or implied |
| $E \approx \left(\frac{1}{2} \times \frac{1}{2}\right)\left[1.2 + 2.95 + 2(1.882 + 2.45 + 2.821)\right]$ | M1 | Correct bracket structure: first $P$ value plus last $P$ value, inner bracket multiplied by 2 containing remaining $P$ values. Allow recovery of invisible brackets. M0 if $t$ values used instead of $P$ values |
| | A1ft | Correct bracket $[\ldots]$ following through their values from (a) |
| $E \approx 4.61$ (kWh) | A1 | cao, must be to 2 d.p. (exact answer via integration is 4.643439737) |

---
7.

Figure 1

Solar panels are installed on the roof of a building.

The power, $P$, produced on a particular day, in kW , can be modelled by the equation

$$P = 0.95 + 2 ^ { t - 12 } + 2 ^ { 12 - t } - ( t - 12 ) ^ { 2 } \quad 8.5 \leqslant t \leqslant 15.2$$

where $t$ is the time in hours after midnight. The graph of $P$ against $t$ is shown in Figure 1.

A table of values of $t$ and $P$ is shown below, with the values of $P$ given to 4 significant figures where appropriate.

\begin{center}
\begin{tabular}{ | l | c | c | c | c | c | }
\hline
\begin{tabular}{ l }
Time, $t$ \\
(hours) \\
\end{tabular} & 10 & 10.5 & 11 & 11.5 & 12 \\
\hline
\begin{tabular}{ l }
Power, $P$ \\
(kW) \\
\end{tabular} &  & 1.882 & 2.45 &  & 2.95 \\
\hline
\end{tabular}
\end{center}
\begin{enumerate}[label=(\alph*)]
\item Use the given equation to complete the table, giving the values of $P$ to 4 significant figures where appropriate.

The amount of energy, in kWh , produced between 10:00 and 12:00 can be found by calculating the area of region $R$, shown shaded in Figure 1.
\item Use the trapezium rule, with all the values of $P$ in the completed table, to find an estimate for the amount of energy produced between 10:00 and 12:00. Give your answer to 2 decimal places.\\
7.\\
\includegraphics[max width=\textwidth, alt={}, center]{52c90d0e-a5e4-45fa-95a4-9523287e7588-20_769_1038_116_450}
\end{enumerate}

\hfill \mbox{\textit{Edexcel P2 2021 Q7 [6]}}