Mathematics

Problem

\tan^{-1} \frac{x-1}{x+2} + \tan^{-1} \frac{x+1}{x+2} = \frac{\pi}{4}

, then

x =

(a)

\frac{1}{\sqrt{2}}

(b)

-\frac{1}{\sqrt{2}}

(c)

\pm\sqrt{\frac{5}{2}}

(d)

\pm\frac{1}{2}