Higher June 2018 Paper 5 Q12
12 Carol says that \(64^{-\frac{1}{2}} = \dfrac{1}{32}\).
Explain her error and give the correct value of \(64^{-\frac{1}{2}}\) in the form \(\dfrac{p}{q}\). [3]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| She divided by 2 and did not square root oe | B1 | Must mention divide by 2 oe accept in symbols e.g. ÷ 2 and square rooting. Accept \(\sqrt{\phantom{x}}\) or [square] root for square root Each step must be correctly evaluated but FT previous step Allow method marks in either order | |
| \(\dfrac{1}{8}\) | 2 | M1 for square root [8 seen in answer] M1 for reciprocal [implied by answer of form \(\dfrac{1}{n}\), \(n \ne 0\) or 32] | |