why it shows no curve in this code?

f=@(x)(2+cos(x.^2))/(3*x.^2+4-x);

y=f(x);

plot (x,y)

Answer 1

[Star Strider]

The reason no plot appears is that ‘y’ is a single point, and the plot function only draws lines between pairs of points and will not plot single points (unless a marker is specified).

Your code has the most common problem I see here on Answers:

f=@(x)(2+cos(x.^2)).*exp(0.01*x)/(3*x.^2+4-x);

↑

The division needs to be element-wise, so ‘./’ instead of ‘/’.

h=0.0001;
x=0:h:3;
f=@(x)(2+cos(x.^2)).*exp(0.01*x)./(3*x.^2+4-x);
y=f(x);
%%first derivativ
plot (x,y)

And with that correction, it works!

.

[Aktaruzzaman shuvo]

thank you so much @Star Strider

[Star Strider]

As always, my pleasure!