Jambmaths question:
What is the common ratio of the G.P $(\sqrt{10}+\sqrt{5})+(10+2\sqrt{5})+\cdot \cdot \cdot $ ?
Option A:
3
Option B:
5
Option C:
$\sqrt{2}$
Option D:
$\sqrt{5}$
Jamb Maths Solution:
$\begin{align} & \text{Common ratio}=r=\frac{2nd\text{ term}}{\text{1st term}} \\ & r=\frac{\sqrt{10}+2\sqrt{5}}{\sqrt{10}+\sqrt{5}}=\frac{(\sqrt{10}+2\sqrt{5})(\sqrt{10}-\sqrt{5})}{(\sqrt{10}+\sqrt{5})(\sqrt{10}-\sqrt{5})} \\ & r=\frac{10+2\sqrt{50}-\sqrt{50}-10}{10-5}=\frac{\sqrt{50}}{5}=\frac{5\sqrt{2}}{5} \\ & r=\sqrt{2} \\\end{align}$
Jamb Maths Topic:
Year of Exam: