1] (4√5-√2)(4√2+√5)
2] 2/√3 - √3/7
3] 已知1/√2 = 0.707 107,準確至六位小數. 求√2的值,準確至四位小數.
我要步驟+答案牙唔該.
F.3 MATHS
2006-10-17 7:46 am
回答 (1)
2006-10-17 7:56 am
✔ 最佳答案
1] (4√5-√2)(4√2+√5)= (4√5)(4√2) + (4√5)(√5) - (√2)(4√2) - (√2)(√5)
= 16√10 + 4 * 5 - 4 * 2 - √10
= 15√10 + 20 - 8
= 15√10 + 12
2] 2/√3 - √3/7
= 2√3 / [√3 * √3] - (√3) / 7
= [2√3] / 3 - (√3) / 7
= [14√3 - 3√3] / 21
= (11√3) / 21
3] 已知1/√2 = 0.707 107
0.707 107 = 1 / √2 = √2 / [√2 * √2] = (√2) / 2
故2 * 0.707107 = √2
√2 = 1.414214
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