cot−11x\cot ^{-1} \frac{1}{x}cot−1x1
tan−11x\tan ^{-1} \frac{1}{x}tan−1x1
tan−1x\tan ^{-1} xtan−1x
2tan−11x2 \tan ^{-1} \frac{1}{x}2tan−1x1
