Respuesta :

This isn't true. If [tex]x=\dfrac\pi4[/tex], you get

[tex]2\csc\left(2\times\dfrac\pi4\right)=2\csc\dfrac\pi2=2[/tex]

while

[tex]\csc^2\dfrac\pi4+\tan\dfrac\pi4=\left(\sqrt2\right)^2+1=3[/tex]