If cos–1 = 2tan–1 x then x = | MATH - INVERSE TRIGONOMETRIC FUNCTIONS | SolveeIt | Solveeit

Today, August 19

Question

If cos^–1 = 2tan^–1 x then x =

A

xĪ R

B

|x| £ 1

C

x Ī (–1, 1]

D

x Ī [1, )

Answer

x Ī [1, )

Explanation

Solution

p > 2tan^–1x ³ 0 Ž $\frac { \pi } { 2 }$ > tan^–1x ³ 0

also 1 + x² ³ 1 – x² Ž x ³ 0