Edexcel C1 — Question 2 4 marks

Exam BoardEdexcel
ModuleC1 (Core Mathematics 1)
Marks4
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TopicIndices and Surds
TypeSimplify numerical surds
DifficultyEasy -1.8 This is a straightforward surd simplification requiring only the recognition that 22.5 = 225/10 = (15²×10)/100, leading to factoring out a perfect square. It's a routine C1 exercise testing basic manipulation of surds with minimal steps, making it easier than average.
Spec1.02b Surds: manipulation and rationalising denominators
2. Express \(\sqrt { 22.5 }\) in the form \(k \sqrt { 10 }\).
AnswerMarks Guidance
\(\sqrt{\frac{45}{2}} = \frac{3\sqrt{5}}{\sqrt{2}}\)M1 A1
\(= \frac{3\sqrt{5}}{\sqrt{2}} \times \frac{\sqrt{2}}{\sqrt{2}} = \frac{3\sqrt{10}}{2}\)M1 A1 (4) 
$\sqrt{\frac{45}{2}} = \frac{3\sqrt{5}}{\sqrt{2}}$ | M1 A1 |
$= \frac{3\sqrt{5}}{\sqrt{2}} \times \frac{\sqrt{2}}{\sqrt{2}} = \frac{3\sqrt{10}}{2}$ | M1 A1 | (4)
2. Express $\sqrt { 22.5 }$ in the form $k \sqrt { 10 }$.\\

\hfill \mbox{\textit{Edexcel C1  Q2 [4]}}
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