"Lim (cos(1/x))^(x^2) as x--> infinity"
Well, first look at what's put inside the cosine function. As x approaches infinity when you have 1/x, that's 1 being divided by VERY large numbers which we can thus conclude is equivalent to 0. Taking the cos(0) you'll get 1.
So now we have 1^(x^2) as x approaches infinity, but the (x^2) is now kinda useless at this point; 1 raised to any power is 1.
Thus, the limit is 1.