Q57 / 150 · MHT CET 2016 · MathematicsQ184 / 184 · MHT CET 2016 · Mathematics · Inverse Trigonometric Functions · Principal Value and BasicsPractise ModeOffIf 2tan-1cosx=tan-1(2coscex) then sinx+cosx=A22Correct answerB2C12D12SolutionAs given, 2tan-1 cos x=tan-1 (2cosce x)tan-1 cos x+tan-1 cos x=tan-1 (2cosce x)Since cos x ≤ 1 =tan-1 2cos x1-cos2 x=tan-1 (2cosce x)⇒ 2cos xsin2 x=2cosce x⇒ 2cot x=2⇒ cot x=1⇒ x=π4Hence,sin x+cos x=sinπ4+cosπ4=12+12=2Hence, the correct answer is option: 'B'.PreviousNext