Plotting function in Maxima So, I've been given an assignment for my new course and unfortunately, the introduction to Maxima tutorial is only the day before the assignment is due which I find to be rather poor planning. 
Therefore, I'd like to get some help here to complete this assignment.
The question is this:

I'm trying to plot this in Maxima, I'm able to plot the Airy functions just fine, but I can't seem to make any progress plotting f1 and f2. I've even tried plotting pieces of them at a time with no luck. 
Clearly, I'm not understanding how to talk to Maxima, and I haven't found any walkthroughs on YouTube of similar problems. 
This is what I have so far:

Surely, Maxima understands it if I've asked it to evaluate and it's giving me the correct expression back?
EDIT: This is the command I am using:

Wolfram Alpha clearly plots this function as:

Can anyone help?

In maxima, use %pi to input the constant $\pi$. pi is just an ordinary variable (undefined in your case). Something like the following
f1(x) := 1/(sqrt(%pi)*(-x)^(1/4))*sin(2*(-x)^(3/2)/3 + %pi/4);
plot2d([airy_ai(x),f1(x)],[x,-15,-0.05]);

will work.
