plotting function which contain zero denominator term

I have a function : . I need to plot a graph between x Vs g(x) where

, I just need values of x from o to ∞ without x=1 because it will give me which doest not make sense.

My Question: How can I use "if and elseif" syntax to plot grap between x Vs g(x) excluding value x=1 and inclusing rest of others.

[Walter Roberson]

g(x) is infinite or undefined because f(1) is infinity . How would you plot a graph "between" something and an infinite or undefined value?

[shree thapa]

You can choose value of x from 0 to 100.

[shree thapa]

Yes, that is the question, we need to ignore the graph x=1 and plot for other vlaues.

[Walter Roberson]

Okay, so suppose I choose x = 7. Then what would the expected plot be? is constant because the integral "uses up" all of the unbound variables in f(x)

[shree thapa]

Yes, You right x is variable so you will get different g(x) for different x so the just plot.

Answer 1

[Walter Roberson]

syms x
f(x) = 1/(1-x^2)

f(x) = 

g(x) = int(f(x), x, 0, inf)

g(x) = 

NaN

g(x) is always undefined, no matter what the value of x is.

ratio = f(x)/g(x)

ratio = 

NaN

fplot(ratio, [0 20])

Notice the plot is empty. Because every entry is NaN.

[Walter Roberson]

syms x
f(x) = piecewise(x < 1, 1/(1-x^2), x == 1, 0, -1/(1-x^2))

f(x) = 

a = int(f(x), x, 0, 1)

a = 

∞

b = int(f(x), x, 1, inf)

b = 

∞

a+b

ans = 

∞

g(x) = int(f(x), x, 0, inf)

g(x) = 

∞

ratio = f(x)/g(x)

ratio = 

0

fplot(ratio, [0 20])

So you can define away the integral so that you do not get nan (by integrating a different function), but you are stuck with the problem that g(x) is constant.