MathematicsEasy66×since 2002Q4058The trigonometric equation sin−1x=2sin−1a{\sin ^{ - 1}}x = 2{\sin ^{ - 1}}asin−1x=2sin−1a has a solution for :A∣a∣≥12\left| a \right| \ge {1 \over {\sqrt 2 }}∣a∣≥21B12<∣a∣<12{1 \over 2} < \left| a \right| < {1 \over {\sqrt 2 }}21<∣a∣<21Call real values of aaaD∣a∣≤12\left| a \right| \le {1 \over {\sqrt 2 }}∣a∣≤21Check answerSkip