> Find: > lim (t+1)^9 * (t^2-1) > x --> -2 > Would you just substitute in the -2 for the t's and figure it out > algebraically? >
Sure, you don't need limits to figure this one out, limits should be used when you can't just plug in the numbers, for example, sinx/x for x-->0 or (1+x)^x for x-->0. There are some artificially cooked situations when you plug in and get the wrong number, for example, f(x)=1 for x=/=0, f(0)=0, then lim (x-->0) f(x) = 1, while f(0)=0. But if you deal with expressions involving the elementary functions, you can plug in and get the limit. It's because the elementary functions are continuous.