Question 6 - A-Level Maths

Exam Board	OCR MEI
Module	C2 (Core Mathematics 2)
Year	2010
Session	January
Topic	Geometric Sequences and Series

Find the 51 st term of the sequence given by $$\begin{aligned} u _ { 1 } & = 5
u _ { n + 1 } & = u _ { n } + 4 \end{aligned}$$
Find the sum to infinity of the geometric progression which begins $$5 \quad 2 \quad 0.8 \quad \ldots .$$ \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{053009a4-e88f-4711-ad97-cebb1740744b-3_531_969_744_589} \captionsetup{labelformat=empty} \caption{Fig. 7}
\end{figure} Fig. 7 shows triangle ABC , with $\mathrm { AB } = 8.4 \mathrm {~cm}$. D is a point on AC such that angle $\mathrm { ADB } = 79 ^ { \circ }$, $\mathrm { BD } = 5.6 \mathrm {~cm}$ and $\mathrm { CD } = 7.8 \mathrm {~cm}$. Calculate
angle BAD ,
the length BC .