Question

If $x = \log(y + \sqrt{y^{2} + 1}),$ then $y =$

• A. $\tanh x$
• B. $\coth x$
• C. $\sinh x$
• D. ${\cos h}x$

Answer 1

Answer: (C)

$\sinh x$

Answer 2

$x = \sinh^{- 1}{}$ ⇒ $y = {\sin h}x$