<span>sin22</span>°<span>cos23</span>° <span>+ cos22</span>°<span>sin23</span>° = sin (22° + 23°) = sin 45° = (√2)/2
1 вариант решения
Cos2x=cos^2x-sin^2x
Cos2x=(-0.7)^2-sin^2x
Sin^2x=1-(0.7)^2=1-0.49=0.51
Cos2x=(-0.7)^2-0.51=0.49-0.51=-0.02
2 вариант
Cos2x=2cos^2x-1=2*(-0.7)^2-1=2*0.49-1=0.98-1=-0.02