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zhenyu zeng


9 total contributions since 2019

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Answered
Why the last row is wrong?
Wrong: sym.charToFunction (line 26) Invalid variable name. Wrong: sym/collect (line 40) x = sym.charToFunction(x);

14 jours ago | 0

Question


Why the last row is wrong?
t=sym('t','positive') ut=str2sym('Heaviside(t)-Heaviside(t-1)') ht=t*exp(-t) yt=int(subs(ut,t,tao)*subs(ht,t,t-tao),tao,0,t) ...

14 jours ago | 1 answer | 0

1

answer

Question


What is the meaning of 'simplify(n./d)?
What is the meaning of 'simplify(n./d)? I feel n./d is weird. syms x A=[3/2 (x^2+3)/(2*x-1)+3*x/(x-1);4/x^2,3*x+4] pretty...

28 jours ago | 1 answer | 0

1

answer

Question


expr2=collect(EXPR,'exp(-t)') Why is it wrong?
EXPR=str2sym('(x^2+x*exp(-t)+1)*(x+exp(-t))') expr1=collect(EXPR) expr2=collect(EXPR,'exp(-t)') Why expr2 shows: sym.charTo...

28 jours ago | 1 answer | 0

1

answer

Question


Why is it wrong: e3=sym('sin(x)^2+cos(x)=0')
Why is it wrong: e3=sym('sin(x)^2+cos(x)=0')

28 jours ago | 2 answers | 0

2

answers

Question


four dimensions array's expression
A=rand(2,3,3) B=cat(4,A(:,:,1),A(:,:,2),A(:,:,3)) B(:,:,1,1)= B(:,:,1,2)= B(:,:,1,3)= B(:,:,1,4)= Why not B(:,:,1,1)= B(...

environ 2 mois ago | 2 answers | 0

2

answers

Question


What is the meaning of [B,J]=sort(A,'descend')?
What is the meaning of [B,J]=sort(A,'descend') Why can he use [B,J] here?

environ 2 mois ago | 0 answers | 0

0

answers

Question


A(B)=0 What is its meaning?
A=rand(5) B=A>0.8 A(B)=0 Can you tell me what is A(B)=0 meaning?

3 mois ago | 2 answers | 0

2

answers

Question


Why does it become four number in a line?
>>A(0 0 0;0 2 2) >>A(1:2)=[] A= 0 2 0 2 Why A becomes 0 2 0 2 not becomes (0 2;0 2)?

3 mois ago | 2 answers | 0

2

answers