Find and display intersections using fzero

I have two functions: f(x) = x.^2-1, f(g) = exp(x/5) in a linspace(-2,2). I need to indicate on the graph where f = g using the fzero function. Also I would like to keep it in a single m file.

Thanks

Answer 1

[Brendan Hamm]

If f(x) = g(x) then f(x) - g(x) = 0. So we need to define h(x) = f(x) - g(x) and find where h(x) = 0. This is exactly what fzero is made for.

h = @(x) x.^2 - 1 - exp(x/5); % Creates a function handle for your function

Now let's plot and see if we can find a point close to where this function is zero.

x = -2:0.01:2;
plot(x,h(x));

Looks like -1.5 and 1.5 are close.

firstZero = fzero(h,-1.5);
secondZero = fzero(h,1.5);

Now visualize these on the plot:

hold on

plot(firstZero,h(firstZero),'ro');
plot(secondZero,h(secondZero),'ro'); 

hold off

[Carlos]

Thanks that's exactly what I needed. I used f(firstZero) and g(firstZero) rather than h to graph the point of intersection.

[Brendan Hamm]

Awesome. If you found this to solve your problem, please accept the answer so others with similar issues can find the solution.