Understanding Powers and Recurring Decimals in GCSE Mathematics
When working with ocr maths paper 5 topics, students often encounter questions about powers and decimal conversions. Let's explore these fundamental concepts that frequently appear in j560/05 paper 5 (higher tier practice paper).
In examining powers with negative exponents, many students make errors similar to Carol's misconception about 64^(-1/2). The correct approach involves understanding that a negative power means we need to find the reciprocal, and the fraction means we need to find the square root. When calculating 64^(-1/2), we first find the square root of 64 (which is 8) and then take its reciprocal, giving us 1/8 or 0.125.
Definition: A negative exponent means we take the reciprocal of the number raised to the positive version of that exponent. For example, x^−n = 1/xn
Converting between recurring decimals and fractions is another crucial skill tested in ocr maths paper 5 2022 mark scheme. When converting 5/12 to a recurring decimal, we perform the division, identifying the pattern that repeats. In this case, 5 ÷ 12 = 0.416666... where 6 is the recurring digit.
Example: To convert 0.76 to a fraction:
- Let x = 0.76666...
- Multiply both sides by 10: 10x = 7.6666...
- Subtract x from 10x: 9x = 7
- Therefore x = 7/9