OCR C1 2012 January — Question 4 5 marks

Exam BoardOCR
ModuleC1 (Core Mathematics 1)
Year2012
SessionJanuary
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicIndices and Surds
TypeEvaluate numerical powers
DifficultyEasy -1.8 This is a straightforward recall question testing basic index laws and surd simplification with no problem-solving required. Each part is a single-step calculation using standard rules (negative indices, fractional indices, surd division), making it significantly easier than average A-level questions which typically require multi-step reasoning.
Spec1.02a Indices: laws of indices for rational exponents1.02b Surds: manipulation and rationalising denominators

4 Evaluate
  1. \(3 ^ { - 2 }\),
  2. \(16 ^ { \frac { 3 } { 4 } }\),
  3. \(\frac { \sqrt { 200 } } { \sqrt { 8 } }\).

Question 4(i):
AnswerMarks Guidance
AnswerMarks Guidance
\(\frac{1}{9}\)B1
Question 4(ii):
AnswerMarks Guidance
AnswerMarks Guidance
\(\left(\sqrt[4]{16}\right)^3\)M1 Interprets the power \(\frac{3}{4}\) correctly. Allow \((\sqrt[4]{16})^3\) or \((\sqrt[4]{16^3})\) or \(\left(16^{\frac{1}{4}}\right)^3\) or \(\left(16^3\right)^{\frac{1}{4}}\)
\(= 8\)A1 \(\pm 8\) is A0
Question 4(iii):
AnswerMarks Guidance
AnswerMarks Guidance
\(5\sqrt{8} \div \sqrt{8}\)M1 \(\sqrt{100}\,\sqrt{2}\div\sqrt{4}\,\sqrt{2}\) or \(\sqrt{\frac{200}{8}}\) or \(\sqrt{25}\,\sqrt{8}\div\sqrt{8}\) or \(\sqrt{1600}\div 8\) soi
\(= 5\)A1 Condone \(\pm 5\)
## Question 4(i):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $\frac{1}{9}$ | B1 | |

---

## Question 4(ii):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $\left(\sqrt[4]{16}\right)^3$ | M1 | Interprets the power $\frac{3}{4}$ correctly. Allow $(\sqrt[4]{16})^3$ or $(\sqrt[4]{16^3})$ or $\left(16^{\frac{1}{4}}\right)^3$ or $\left(16^3\right)^{\frac{1}{4}}$ |
| $= 8$ | A1 | $\pm 8$ is **A0** |

---

## Question 4(iii):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $5\sqrt{8} \div \sqrt{8}$ | M1 | $\sqrt{100}\,\sqrt{2}\div\sqrt{4}\,\sqrt{2}$ or $\sqrt{\frac{200}{8}}$ or $\sqrt{25}\,\sqrt{8}\div\sqrt{8}$ or $\sqrt{1600}\div 8$ soi |
| $= 5$ | A1 | Condone $\pm 5$ |

---
4 Evaluate\\
(i) $3 ^ { - 2 }$,\\
(ii) $16 ^ { \frac { 3 } { 4 } }$,\\
(iii) $\frac { \sqrt { 200 } } { \sqrt { 8 } }$.

\hfill \mbox{\textit{OCR C1 2012 Q4 [5]}}