| Exam Board | OCR MEI |
|---|---|
| Module | C1 (Core Mathematics 1) |
| Year | 2015 |
| Session | June |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Indices and Surds |
| Type | Evaluate numerical powers |
| Difficulty | Easy -1.8 This is a straightforward recall question testing basic index laws: anything to the power 0 equals 1, and negative/fractional powers. Both parts are direct one-step calculations requiring only memorized rules with no problem-solving, making it significantly easier than average A-level questions. |
| Spec | 1.02a Indices: laws of indices for rational exponents |
| Answer | Marks | Guidance |
|---|---|---|
| Answer | Marks | Guidance |
| \(1\) | B1 |
| Answer | Marks | Guidance |
|---|---|---|
| Answer | Marks | Guidance |
| \(\frac{3}{5}\) or \(0.6\) | B3 | Allow B3 for \(\pm 0.6\) oe |
| M1 for \(\left(\frac{25}{9}\right)^{-\frac{1}{2}} = \left(\frac{9}{25}\right)^{\frac{1}{2}}\) soi or \(\frac{1}{\left(\frac{25}{9}\right)^{\frac{1}{2}}}\) | M1 | M1 for inversion even if they have done something else first; may be earned after 2nd M1 for inversion of their \(\frac{5}{3}\) |
| and M1 for at least one of 3 and 5 found | M1 |
## Question 3(i):
| Answer | Marks | Guidance |
|--------|-------|----------|
| $1$ | B1 | |
## Question 3(ii):
| Answer | Marks | Guidance |
|--------|-------|----------|
| $\frac{3}{5}$ or $0.6$ | B3 | Allow B3 for $\pm 0.6$ oe |
| M1 for $\left(\frac{25}{9}\right)^{-\frac{1}{2}} = \left(\frac{9}{25}\right)^{\frac{1}{2}}$ soi or $\frac{1}{\left(\frac{25}{9}\right)^{\frac{1}{2}}}$ | M1 | M1 for inversion even if they have done something else first; may be earned after 2nd M1 for inversion of their $\frac{5}{3}$ |
| and M1 for at least one of 3 and 5 found | M1 | |3 Evaluate the following.\\
(i) $200 ^ { \circ }$\\
(ii) $\left( \frac { 25 } { 9 } \right) ^ { - \frac { 1 } { 2 } }$
\hfill \mbox{\textit{OCR MEI C1 2015 Q3 [4]}}