Chapter 1 - Functions and Limits - 1.1 Four Ways to Represent a Function - 1.1 Exercises - Page 23: 74

the function f is an even function

Calculate $f(t)$ and $f(-t)$ $f(t)=\frac{t^{2}}{t^{4}+1}$ $f(-t)=\frac{(-t)^{2}}{(-t)^{4}+1}=\frac{t^{2}}{t^{4}+1}$ therefore we can see that the function f is an even function that satisfies $f(-x)=f(x)$ for every x in the domain.