5.ecuatia dreptei este
AB:(y-YA)/(yB-yA)=(x-xA)/(xB-xA)
A(4,-3) si B(3,-4)
AB:
(y+3)/(-4+3)=(x-4)/(3-4)
AB: (y+3)/(-1)=(x-4)/(-1)
y+3=x-4
x-y=7
6.
cos²120=(1+cos240)/2=(1-√3/2)/2=(2-√3)/4
sin²60=(1-cos 120)/2=(1-√3/2)/2=(2-√3)/4
cos²120+sin²60=(2-√3)/4+(2-√3)/4=2(2-√3)/4=(2-√3)/2