Question

tg0°-2ctg90°-sin0°-3cos90°=

Answer 1

1) cos720+tg 30 ctg 210+sin 120 = сos2*360° + tg30°ctg(180° + 30°) + 
+ sin(90° + 30)° = 1 + 1/√3*ctg30° + sin30° = 1 + (1/√3)*(√3) + 1/2 = 1 + 1 + 1/2 = 2(1/2)
tg0 °- 2ctg90° - sin0° - 3cos90° = 0 - 2*0 - 0 - 3*0 = 0