1)sina=-√1-144/169=-√25/169=-5/13
78sina=78*(-5/13)=-30
2)ctga=1/2
5(cos²a+sin²a)-4ctga=5-4*1/2=5-2=3
3)33√2cos(360+135)=33√2cos135=33√2cos(180-45)=-33√2cos45=-33√2*√2/2=-33
4)2cos120/c/(cos(180-60)-sin(180-30))=2cos(180-60)/(-cos60-sin30)=
=-2ccos60/(-1/2-1/2)=-2*1/2/(-1)=1
5)3cos²a+3:1/sin²a -22,4=3cos²a+3sin²a-22,4=3(cos²a+sin²a)-22,4=3-22,4=-19,4