Plot shows a negative graph

hi, I need a positive exponential graph starting from zero. but it shows negative. what could I do now to get a positive exponential graph starting from zero? the coding is as follows,

u=0.02; i=22/7; g=800; l=2;
d=0.1; p=45; m=tand(p);
r=linspace(0,1,100);
a=(r-m*(d+l)).^5-((r-m*1).^5)
q=(i*g*a)./(40*u*m)
plot(r,q)

Answer 1

[madhan ravi]

Add the below two lines at the end of your code

xlim([-1 1]) % if you change the scale it is clear that it starts from zero
grid on

[Abhinandana R]

but sir the q term(y axis) is still negative. I need it in a positive plot

[madhan ravi]

plot(r,abs(q))

[Abhinandana R]

thank you sir!