$\tan ^{-1}\left(\frac{1}{4}\right)+\tan ^{-1}\left(\frac{2}{9}\right)$ equal to-

• A

  $\frac{1}{2} \cos ^{-1}\left(\frac{3}{5}\right)$
• B

  $\frac{1}{2} \sin ^{-1}\left(\frac{3}{5}\right)$
• C

  $\frac{1}{2} \tan ^{-1}\left(\frac{3}{5}\right)$
• Correct answer
  D

  $\tan ^{-1}\left(\frac{1}{2}\right)$

Hence, the correct answer is option: 'D'.