1.By using a calculator, calculate √7-√2 / √7 +√ 2 .(corr. to 2 decimal place)
2. Given that the length of an equilateral triangle is a, find its area.
中二數學題(easy)
2009-01-11 4:01 am
回答 (3)
2009-01-11 4:19 am
✔ 最佳答案
√7-√2 /√7 +√2= (√7-√2) (√7-√2)/(√7 +√2) (√7-√2)
= (√7)(√7)-2(√7)(-√2) +(-√2) (-√2) /(√7) (√7)- (-√2) (-√2)
=7-2√14 +2 / 7-2
= 9-2√14 /5
=0.30
let x be the triangle 's height:
((a/2)(a/2) ) /2 +(x) (x))/ 2 = (a) (a)
x = a/2√3
area
(a/2√3 ) a =AREA
aa/2√3 =area
2009-01-11 7:49 pm
is √7-√2 / √7 +√ 2
or(√7-√2 )/ (√7 +√ 2)
or(√7-√2 )/ (√7 +√ 2)
2009-01-11 4:35 am
1.
√7 - √2 / √7 + √ 2
= [(√7)(√7) - √2 + (√7 )(√ 2)] / √7
= (7 - √2 + √14) / √7
= 3.53
2.
Area of an equilateral triangle = (1/2)a^2
2009-01-10 21:10:13 補充：
2.
area of an equilateral triangle = (1/2)a^2(sin 60)
√7 - √2 / √7 + √ 2
= [(√7)(√7) - √2 + (√7 )(√ 2)] / √7
= (7 - √2 + √14) / √7
= 3.53
2.
Area of an equilateral triangle = (1/2)a^2
2009-01-10 21:10:13 補充：
2.
area of an equilateral triangle = (1/2)a^2(sin 60)
參考: me., me.
收錄日期: 2021-04-25 22:24:23
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