4 sin(-7п/4) cos(-4п/3) ctg3п/4

[latex]4sin(-frac{7pi}{4})cdot cos(-frac{4pi}{3})cdot ctgfrac{3pi}{4}=\\=4sin(frac{pi}{4}-2pi )cdot cos(-pi-frac{pi}{3})cdot ctg(pi -frac{pi}{4})=\\=4cdot Big (-sin(2pi-frac{pi}{4})Big )cdot cos(pi+frac{pi}{3})cdot (-ctgfrac{pi}{4})=\\=4cdot sin(-frac{pi}{4})(-cosfrac{pi}{3})cdot ctgfrac{pi}{4}=4cdot (-sinfrac{pi}{4})cdot (-frac{1}{2})cdot 1=\\=4cdot frac{sqrt2}{2}cdot frac{1}{2}=sqrt2[/latex]