Integration in m file

Really struggling with how integration works in matlab, I want to calculate the area under the function x+3 with limits 0 and where x+3 meets tan(x).

I have this but cannot get it to run.

thanks for any help

uplim = fzero(@(x) tan(x)-x-3,1.2)

function y=integrand(x);
y=(x+3); 
I1=quad('integrand',0,uplim)

[Brian]

For clarity this is the original question:

"Calculate the area confined by the functions f(x)=x+3 and g(x)=tan(x) in the first positive interval. From x=0 to the first positive intersection point (where f(x)= g(x)). "

I may have misinterpreted it

Answer 1

[Roger Stafford]

Yes, I think you did misinterpret it. The question asks for the area "confined by the functions f(x)=x+3 and g(x)=tan(x)", not the area under f(x). You need f(x)-g(x) as an integrand. Make a plot of both functions and you'll see the difference.

[Brian]

This is what I have:

uplim = fzero(@(x) tan(x)-x-3,1.2)

function y=integrand(x); y=((x+3)-tan(x)); end

 I1=quad('integrand',0,1.3446)

I can get it to run seperately to get an answer but not in single file. Please help, thanks