why does it tell me "index exceeds matrix dimensions"??

I'm trying to run the following code:

x = 10:30; y = exp((-2139.2) ./ (x - 34.42));

A = [x ; y(x)]

plot(x,y,'b','lineWidth',2.5); grid; xlabel('temperature in degree celcius','Fontsize',16); ylabel('vapor pressure','Fontsize',16)

But when I try, it tells me that index exceeds matrix dimensions.

Can somebody help?

[Jacky Jo]

X has 21 values.

Y has the same.

but when we do operation y(x) =y(20:30),

we are trying to call values from 20 to 30 in y which is impossible since y just has values from 1 to 21.

So you have to change the code for y(i) where i could be only vary from 1 to 21.

ex:

A = [x ; y(1:21)];

Answer 1

[Kirby Fears]

You do not need to write y(x). You have already defined y, so just call it y. Code fixed below:

x = 10:30;

y = exp((-2139.2) ./ (x - 34.42));

A = [x ; y];

plot(x,y,'b','lineWidth',2.5); 
grid;
xlabel('temperature in degree celcius','Fontsize',16);
ylabel('vapor pressure','Fontsize',16)

Answer 2

[Star Strider]

you defined ‘y’ as an array, not a function, so you cannot call it as a function.

This works:

A = [x ; y];