x =
- 6 ± √( 6 )² - 4( -1 ) ( 11 )
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
2 ( -1 )
之後點計??
hints :: answ = 3±2√5
F4 MATHS
2006-10-16 6:03 am
回答 (5)
2006-10-16 6:07 am
✔ 最佳答案
- 6 ± √( 6 )² - 4( -1 ) ( 11 )﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
2 ( -1 )
-6±√(36+44)
=---------------------
-2
-6±4√5
=----------
-2
=3±2√5
2006-10-16 6:12 am
........-6±√36+44
x =﹉﹉﹉﹉﹉﹉
..................-2
............-6±√80
x =﹉﹉﹉﹉﹉﹉
..................-2
........-6±√4×4×5
x =﹉﹉﹉﹉﹉﹉
.................-2
...........-6±4√5
x =﹉﹉﹉﹉﹉﹉
...............-2
...........-2(3±2√5)
x =﹉﹉﹉﹉﹉﹉
.................-2
∴ x =3±2√5
x =﹉﹉﹉﹉﹉﹉
..................-2
............-6±√80
x =﹉﹉﹉﹉﹉﹉
..................-2
........-6±√4×4×5
x =﹉﹉﹉﹉﹉﹉
.................-2
...........-6±4√5
x =﹉﹉﹉﹉﹉﹉
...............-2
...........-2(3±2√5)
x =﹉﹉﹉﹉﹉﹉
.................-2
∴ x =3±2√5
2006-10-16 6:09 am
{-6 ± sq root [6^2-4(-1)(11)]} / [2(-1)]
=[-6 ± sq root (36+44)] / (-2)
=[-6 ± sq root(80)] / (-2)
=3 ± sq root (20)
=3 ± 2 sq root (5)
Got it?
the most difficult part is
sq root (80)
= sq root (4*20)
= sq root (4) * sq root (20)
= 2 * sq root (20)
= 2 * sq root (4*5)
= 2 * sq root (4) * sq root (5)
= 2 * 2 * sq root (5)
=[-6 ± sq root (36+44)] / (-2)
=[-6 ± sq root(80)] / (-2)
=3 ± sq root (20)
=3 ± 2 sq root (5)
Got it?
the most difficult part is
sq root (80)
= sq root (4*20)
= sq root (4) * sq root (20)
= 2 * sq root (20)
= 2 * sq root (4*5)
= 2 * sq root (4) * sq root (5)
= 2 * 2 * sq root (5)
2006-10-16 6:08 am
- 6 ± √ 36 + 44
﹉﹉﹉﹉﹉﹉
-2
- 6 ± √ 80
﹉﹉﹉﹉﹉﹉
-2
- 6 ± 4√ 5
﹉﹉﹉﹉﹉﹉
-2
3 ± 2 √ 5
﹉﹉﹉﹉﹉﹉
-2
- 6 ± √ 80
﹉﹉﹉﹉﹉﹉
-2
- 6 ± 4√ 5
﹉﹉﹉﹉﹉﹉
-2
3 ± 2 √ 5
參考: myself
2006-10-16 6:07 am
-6 ± √( 6 )2 - 4( -1 ) ( 11 )
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
2 ( -1 )
-6 ± √80
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
2 ( -1 )
-6 ± √16*5
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
2 ( -1 )
-6 ± 4√5
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
2 ( -1 )
-2(3± 2√5)
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
-2
3±2√5
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
2 ( -1 )
-6 ± √80
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
2 ( -1 )
-6 ± √16*5
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
2 ( -1 )
-6 ± 4√5
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
2 ( -1 )
-2(3± 2√5)
﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉﹉
-2
3±2√5
收錄日期: 2021-04-26 13:29:04
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061015000051KK06363