For all real numbers x except x=0 and x=1 the function f is defined by f(x/x-1)=1/x. Suppose 0<=t<=pi/2. Given that f(Sec^2t)=(g(t))^2 for some trigonometric function g, find g.
Enter your answer as one of the six options: sin, cos, tan, sec, csc, cot.