(R-a)(R-a)=R^2-b^2
咁 最後求 R = ? 算式呢
(R-a)(R-a)=R^2-b^2 問數學
2008-01-15 5:19 am
回答 (3)
2008-01-15 5:29 am
✔ 最佳答案
(R-a)^2=R^2-2(b)^2 R^2 - 2Ra + a^2 = R^2 - 2(b)^2
2Ra = a^2 + 2(b)^2
R = a/2 + (b)^2/a
2008-01-25 6:48 pm
change to :
R=[(b/2)^2 + a^2]2a
R=[(b/2)^2 + a^2]2a
2008-01-15 6:28 pm
(R-a)^2=R^2-2(b)^2
R^2-2aR+a^2=R^2-2b^2
-2aR=-2b^2-a^2
-2aR=-(2b^2+a^2)
R=(2b^2+a^2)/2a
R^2 - (b/2)^2 = (R-a)^2
R^2 - (b/2)^2 = R^2-2aR+a^2
- (b/2)^2 =-2aR+a^2
2aR=(b/2)^2+a^2
2aR=b^2/4+a^2
2aR=(b^2+4a^2)/4
R=(b^2+4a^2)/8a
R^2-2aR+a^2=R^2-2b^2
-2aR=-2b^2-a^2
-2aR=-(2b^2+a^2)
R=(2b^2+a^2)/2a
R^2 - (b/2)^2 = (R-a)^2
R^2 - (b/2)^2 = R^2-2aR+a^2
- (b/2)^2 =-2aR+a^2
2aR=(b/2)^2+a^2
2aR=b^2/4+a^2
2aR=(b^2+4a^2)/4
R=(b^2+4a^2)/8a
參考: me
收錄日期: 2021-04-14 19:00:09
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080114000051KK03789