=√2/2-√2/2*(-1)=√2/2+√2/2=√2
1) cos^2d=3/4 sin^2d=1-cos^2d=1-3/4=1/4 sind=1/2 tgd=sind/cosd=1/sqrt(3) ctgd=sqrt(3)
2) cos^2d=1-1/2=1/2 cosd=sqrt(2)/2 tgd=crgd=1
3) cos^2d=1-1/4=3/4 cosd=sqrt(3)/2 tgd=1/sqrt(3) ctgd=sqrt(3)
<span>2b(3a+b)-(a-b)^2=</span>6ab+2b^2-a^2+2ab-b^2=8ab+b^2-a^2