Question

The domain of definition of the function $y=3e^{\sqrt{x^2-1}}\log (x-1)$ is

• A. $(1,\infty )$
• B. $[1,\infty )$
• C. set of all reals different from 1
• D. $(-\infty .-1)\cup (1,\infty )$

Answer 1

Answer: (A)

For $D_f,x^2-1\ge 0$ and $x\forall -1>0$
$\Rightarrow |x|\ge 1$ and $x>1\Rightarrow x>1\Rightarrow D_f=(1,\infty )$