Prove two exponential functions g & h with positive coefficients & bases bg & bh have the same order of growth if bg=bh>1, & bg has a higher order of growth than bh if bg>bh>1.
So you mean as t -> infinity? If that is the case then get the model and evaluate it as the limit of t tends to infinity and see if it blows up (becomes infinite in magnitude) or converges to a fixed value.