1.Find the unknown value(取至3位有效數字)
圖片參考：http://imgcld.yimg.com/8/n/HA00744443/o/701108170105313873444720.jpg
2.Make the letter in bracket the subject of the formula.
圖片參考：http://imgcld.yimg.com/8/n/HA00744443/o/701108170105313873444721.jpg
求過程及答案><
F.2 maths (2條問題)
2011-08-18 3:22 am
回答 (2)
2011-08-18 3:56 am
✔ 最佳答案
1. sin30=(x-5)/x1/2=(x-5)/x
x=2(x-5)
x=2x-10
x=10
2. A-B=√(B²-C²) ->[Square both sides]
(A-B)²=B²-C²
A²-2AB+B²-B²=-C²
B(-2A)=-(C²+A²)
B=(C²+A²)/(2A)
參考: Hope I can help you! ^_^ (From me)
2011-08-19 1:31 am
1.
sin30=(x-5)/x
1/2=(x-5)/
x/2=x-5
x=2x-10
-x=-10
x=10
2.
圖片參考：http://imgcld.yimg.com/8/n/HA00336279/o/701108170105313873444720.jpg
a-b=平方根(b^2-c^2)
(a-b)^2=(b^2-c^2)
a^2-2ab+b^2=b^2-c^2
a^2-2ab=-c^2
-2ab=-c^2-a^2
b=(-c^2-a^2)/(-2a)
b=-(c^2+a^2)/-2a
b=(c^2+a^2)/2a
b=(a^2)/2a+(c^2)/2a
b=a/2+c^2/2a
sin30=(x-5)/x
1/2=(x-5)/
x/2=x-5
x=2x-10
-x=-10
x=10
2.
圖片參考：http://imgcld.yimg.com/8/n/HA00336279/o/701108170105313873444720.jpg
a-b=平方根(b^2-c^2)
(a-b)^2=(b^2-c^2)
a^2-2ab+b^2=b^2-c^2
a^2-2ab=-c^2
-2ab=-c^2-a^2
b=(-c^2-a^2)/(-2a)
b=-(c^2+a^2)/-2a
b=(c^2+a^2)/2a
b=(a^2)/2a+(c^2)/2a
b=a/2+c^2/2a
收錄日期: 2021-04-13 18:10:26
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110817000051KK01053