Question

4. (UFMG) Sendo f : R ⇒ R uma função definida por f(x)= x2 –1, calcule:a)$f(\frac{1}{2})$                                                              b)$f(1-\sqrt{2})$

Answer 1

$f(x)=x^2-1$

a) $f\left(\dfrac{1}{2}\right)=\left(\dfrac{1}{2}\right)^2-1=\dfrac{1}{4}-1=\dfrac{1-4}{4}=\boxed{-\dfrac{3}{4}}$

b) $f(1-\sqrt{2})=(1-\sqrt{2})^2-1=1-2\sqrt{2}+2-1=\boxed{2-2\sqrt{2}}$