Number of solutions of the equation arctan [1/(2x^2 + 1)] + arctan [1/(4x^2 + 1) = arctan 2/x^4 is
Number of solutions of the equation: . is
Let: . .
. . Hence: . .
Substitute  and we have: .
Take the tangent of both sides:
Multiply by the LCD,
This simpifies to: .
. . which factors: .
There are two solutions . . . answer (C).