# MATLAB matrices, vectors, and equations help!!!

2 ビュー (過去 30 日間)
Grace Rembold 2019 年 11 月 25 日
Commented: Star Strider 2019 年 11 月 25 日
I'm currently trying to compute values of two different Variables, but the problem is that, while one equation is working, the other isn't. Here is my current code with my matrices included.
INITIAL MATRICES/ VECTORS:
X =
NaN
0.2200
0.3000
0.4400
0.4900
0.7000
0.8000
0.9000
1.1000
1.0000
1.1500
1.2000
1.2200
1.2600
1.2500
1.2700
1.2000
1.2200
1.2600
1.2000
1.2200
1.2600
1.2000
1.2200
1.2600
1.2500
t =
NaN
0
4
7
10
13
16
22
25
30
33
36
40
48
51
55
60
80
100
120
140
160
180
200
220
240
%% Problem 1
%{
X=Cell Mass Concentration (g/L)
U= Cell Mass Yield Per Carbon Monoxide gcells/mmolCO
t= Time (hours)
Mu= Specific Growth Rate
X1=X(1:end-1)
X2=X(2:end)
t1=t(1:end-1)
t2=t(2:end)
Mu=(X2-X1)/(t2-t1)
U=(X2-X1)/CO
%}
X1=X(1:end-1)
X2=X(2:end)
t1=t(1:end-1)
t2=t(2:end)
Mu=(log(X2)-log(X1))./(t2-t1);
U=(X2-X1)/CO;
%{
ans
Max value of Cell Mass Yield per Carbon Monoxide = max(Yx)
Max value of Cell Mass Concentration = max(Mu)
%}
% Find max values of specific growth rate(Mu) and cell mass yield(Yx/co)
Mumax=max(Mu);
Umax=max(U);
sprintf('The maximum specific growth rate is %f, and the maximum cell mass yield per CO is %f',Mumax, Umax)
The problem with my current code is that, while Mu is equalling a vector which 26x1, U is equalling a matrix which is 25x26. I need U to also be a 26x1 vector, because currently my max value for U is 0.00000.

#### 0 件のコメント

サインイン to comment.

### 採用された回答

Star Strider 2019 年 11 月 25 日
The ‘CO’ variable is missing.
If ‘CO’ is a row vector rathar than a column vector, that could be the problem. If so, the solution would be to transpose it to a column vector. Remember to do element-wise operations, if that is what you want.

#### 4 件のコメント

Star Strider 2019 年 11 月 25 日
This produces a (25x1) vector:
U=(X2-X1)./CO(2:end);
That is likely where the dot operator was, however the sizes of the vectors must also be the same.
I do not completely understand what you are doing, especially with respect to ‘X1’ and ‘X2’, and ‘t1’ and ‘t2’.
Grace Rembold 2019 年 11 月 25 日
Thank you, that is where the dot operator was.
the t1, X1, etc. have been removed for everything now. they were just placeholders that made it easier to read while i figured out the actual equation. I'm basically recreating a given equation based off of excel data and then using the equations to plot relationships between the data. in further problems. But to be honest, i'm nto really sure whats going on either :/
Star Strider 2019 年 11 月 25 日
My pleasure.

サインイン to comment.