Question

$\frac{1}{\sqrt{x^{2} - 1}}( - \infty, - 1) \cup (1,\infty)$ equals –

• A. a² cos a + 2a sina
• B. – a² cos a – 2a sin a
• C. $( - \infty, - 1\rbrack \cup (1,\infty)$ + 2a sin^–1 a
• D. None of these

Answer 1

Answer: (C)

$( - \infty, - 1\rbrack \cup (1,\infty)$ + 2a sin^–1 a

Answer 2

The limit equals $\frac { \mathrm { d } } { \mathrm { da } }$ (a² sin^–1 a)

⇒ $\frac { a ^ { 2 } } { \sqrt { 1 - a ^ { 2 } } }$ + 2a sin^–1 a