a)
cos 114= -cos(180-114) =-cos66
cos 115= -cos(180-115) =-cos65
Expresia devine:
cos65+cos66-cos66-cos65 = 0
c)
sin110 = sin(180-110) = sin70
cos110= -cos(180-110) = - cos70
Expresia devine:
sin70+cos70-sin70-cos70 = 0
e)
sin100=sin(180-100) =sin80
cos80 = - cos(180 - 80) = - cos100
sin135 = sin (180 - 135) = sin 45 =√2/2
Expresia devine:
sin80+cos100-sin80-cos100+2·(√2/2)² = 2·(2/4) =4/4 = 1
