Graph not lining up with the function

Graph not automatically lining up with the function x. The t axis goes from -1 to 2 instead of -2 to 2 and the x axis goes from 1 to 3 instead of 0 to 1 like the exp. How do I override the graph axis?

for t=-2:.1:2
    x=exp(-1*t);
    plot(x,t,'-r');
end;