Question. Which of the following are rational functions?
f(x) = 0
f(x)= (3x-1)/(x^2-4x+5)
f(x)=e^x
f(x) =(sinx)/(cosx)
f(x) =-4x^-3+5x^-1+7-18x^2
f(x) = x^1/2 – x+ 8
All polynomials can be thought of as rational functions.