Undefined function 'ln' for input arguments of type 'double'.

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Alvaro Mª Zumalacarregui Delgado
评论： Alvaro Mª Zumalacarregui Delgado 2021-2-22
I am trying to represent a function and before my code has an operation with a Ln, and when I run the app and click the button give this message 'Undefined function 'ln' for input arguments of type 'double'.' how can i solve it?
P = app.P.Value;
Q = app.Q.Value;
a = app.a.Value;
b = app.b.Value;
Xo = app.Xo.Value;
Yo =app.Yo.Value;
K = b.*Xo-a.*Yo;
C3 = (ln(a.*Yo)-ln(Xo))/- K;
C4 = (ln(b.*Xo)-ln(Yo))/- K;
x = 0:0.2:100;
y3 = K./(exp((K*x-K*C3))-b);
plot (app.Axes,x,y3,'r');
hold (app.Axes,'on')
y4 = - K./(exp(K*x-K*C4)-a);
plot (app.Axes,x,y4,'b');
hold (app.Axes,'off')

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采纳的回答

Steven Lord
Steven Lord 2021-2-22
The natural logarithm function in MATLAB is named log not ln. There are also log10 and log2 functions listed in the See Also section at the end of the log documentation page.

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