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#26 Help Me ! » How to use DeMoivre's formula? » 2006-03-21 23:12:40
- coolwind
- Replies: 2
Use it to evaluate
(3/5+j4/5)^100 ?
Thaks~~
#27 Help Me ! » Discrete Recursive Definition » 2005-11-30 00:33:44
- coolwind
- Replies: 2
Give a recursive definition
ex:
Cn=7n
(a)C1=7;
(b)Cn+1=Cn+7;
=====
problem:
1.Cn=n^2 2.Cn=2-(-1)^n ????
thanks!!
#28 Help Me ! » A linear algebra problem » 2005-11-14 04:09:20
- coolwind
- Replies: 1
Suppose that A ia an nXn matrix that satisfies A^2+7A-I=0.Then A is invertible??
ture or false??and why??
#29 Re: Help Me ! » A differential equation problem. » 2005-10-31 01:59:05
Thanks~~!!^^
#30 Help Me ! » A differential equation problem. » 2005-10-30 04:47:54
- coolwind
- Replies: 2
3y'''+ 5y''-y' +7y=0
y(1)=0, y'(1)=0,y''(1)=0
ANS: y=0 is the only solution on any interval containing x=1
WHY????