[tex]3tg^2(\frac{13\pi }{4})-2sen\frac{\pi }{4}.cos\frac{3\pi }{4}[/tex]
[tex]3.tg(585)-2sen(45).cos(135)\\3.1-2.\frac{\sqrt{2} }{2}.-\frac{\sqrt{2} }{2}[/tex]
[tex]3-2.-(\frac{2}{4})\\3+1=4[/tex]
