How to plot simple function

I am trying to plot f(x)= 1/(1+25x^2) but am getting the error: File: drafts.m Line: 2 Column: 18

Invalid expression. When calling a function or indexing a variable,

use parentheses. Otherwise, check for mismatched delimiters.

x=linspace(-1,1,11);

y=(1/(1+(25*x^2));

plot(x,y)

if i change line 2 to y=sin(x) this works so why does this not work in this instance?

Answer 1

[James Tursa]

Error message says to check for mismatched delimiters. So this

y=(1/(1+(25*x^2));

should be this with one fewer paren:

y=1./(1+(25*x.^2));

The / and ^ were changed to the element-wise operators ./ and .^ so that your function is "vectorized" and will work with arrays.

[Ryan Ferrell]

i understand why there needs the be an x. I forgot to write that in the question but why does "1" need to be "1."?

[James Tursa]

I am not changing x to x. and 1 to 1.

I am changing / to ./ and ^ to .^

That is, the dots get attached to the operators / and ^, not to the operands 1 and x

The element-wise operators ./ and .^ are DIFFERENT operators from the matrix operators / and ^