Considering only the principal values of inverse trigonometric functions, the number of positive real values of \( x \) satisfying \(\displaystyle \tan^{-1}(x)+\tan^{-1}(2x)=\frac{\pi}{4} \) is:
\( 2 \)
more than \( 2 \)
\( 1 \)
\( 0 \)