Error using function fplot
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Garrett Crawford
on 11 May 2020
Commented: Ameer Hamza
on 11 May 2020
When typing my code, I keep getting the error of invalid parameter from fplot. Not sure why it keeps coming up. How would I fix this?
Code:
syms x
f(x) = log(x)^4 * exp((-x)^3) * x^2;
val = int(f(x),x,[0,Inf]);
vpa(val)
X = [0.5 : 0.1 : 2.5]
fplot(@(x) f(x),X,'b')
1 Comment
Geoff Hayes
on 11 May 2020
Garrett - what happens if you don't use a symbolic expression? From fplot 'f' input parameter, the first parameter is a function handle. Or, perhaps you can convert the f to a MATLAB function handle with matlabfunction.
Accepted Answer
Ameer Hamza
on 11 May 2020
Edited: Ameer Hamza
on 11 May 2020
You need to specify range with two numbers.
syms x
f(x) = log(x)^4 * exp((-x)^3) * x^2;
val = int(f(x),x,[0,Inf]);
fplot(@(x) f(x), [0.5 2.5],'b')

2 Comments
Ameer Hamza
on 11 May 2020
I think the above solution with fplot() should be acceptable in this case. But if you still want to plot at these specific x-values then you can use plot() instead of fplot. However, as you can see, the graph is not as smooth
syms x
f(x) = log(x)^4 * exp((-x)^3) * x^2;
val = int(f(x),x,[0,Inf]);
X = 0.5:0.1:2.5;
plot(X, f(X), 'b')

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