Question

f : R $\to$ R and g : [0, $\infty$) $\to$ R is defined by f(x) = $x^2$ and g(x) = $\sqrt{x}$ . Which one of the following is not true?

• A. fog (2) = 2
• B. gof (4) = 4
• C. gof (-2) = 2
• D. fog (-4) = 4

Answer 1

Answer: (D)

fog (-4) = 4

Answer 2

$f \left(x\right)=x^{2}g\left(x\right)=\sqrt{x}$
$f o \,g\left(-4\right)=f\left[g\left(-4\right)\right]$ is not defined