PR: x(s)=0, y(s)=s s in [1,t]

RS: x(s)= s, y(s)=t and s in [0,4]

SQ: x(s)=4 y(s)=s s in [t,1]

I changed your t (in the equation for L) with s, cause we have already t as a parameter and not as a dumby variable in the integral.

and the fact that I wrote that s is in ___, is for the integration limits.