MathematicsMedium66×since 2002Q4089The value of tan⁻¹ [1+x2+1−x21+x2−1−x2],\left[ {{{\sqrt {1 + {x^2}} + \sqrt {1 - {x^2}} } \over {\sqrt {1 + {x^2}} - \sqrt {1 - {x^2}} }}} \right],[1+x2−1−x21+x2+1−x2], ∣x∣<12,x≠0,\left| x \right| < {1 \over 2},x \ne 0,∣x∣<21,x=0, is equal to :Aπ4+12cos−1 x2{\pi \over 4} + {1 \over 2}{\cos ^{ - 1}}\,{x^2}4π+21cos−1x2Bπ4+cos−1 x2{\pi \over 4} + {\cos ^{ - 1}}\,{x^2}4π+cos−1x2Cπ4−12cos−1 x2{\pi \over 4} - {1 \over 2}{\cos ^{ - 1}}\,{x^2}4π−21cos−1x2Dπ4−cos−1 x2{\pi \over 4} - {\cos ^{ - 1}}\,{x^2}4π−cos−1x2Check answerSkip