# Quod Erat Demonstrandum

## 2013/01/10

### 誤差

Filed under: Junior Form Mathematics — johnmayhk @ 2:41 下午

“The length of a cube is measured as 50 cm. If the measurement is correct to the nearest 10 cm, find the relative error in calculating the volume of the cube."

$\frac{55^3-50^3}{50^3}$

$\frac{50^3-45^3}{50^3}$

Relative error = (maximum absolute error)/measurement

$55^3-50^3=41375$$50^3-45^3=33875$ 大，故 maximum absolute error 應取較大者。