(1+sqrt(6))^2=1+2sqrt(6)+6=7+2sqrt(6)
Formula: sinx+siny=2.sin((x+y)/2).cos ((x-y)/2)
-V2=2.sin(pí/4).cos((x-y)/2
-V2=2.V2/2.cos((x-y)/2)
-1=cos((x-y)/2)
(x-y)/2=pí
x-y=2.pí
x+y=pí/2
2x=2pí+pí/2, x=pí+pí/4,x=5pí/4
2y=pí/2-2pí,y=pí/4-pí,y=-3pí/4
Korni iz interval /0,2pí/
Obšče: x=5pí/4+2k.pí,y=-3pí/4+2k.pí, k=0,1,-1,2,-2,.......
1)
a^4+20a²b²+100b^4 = (a²+10b²)²
2)
0,25a²+1,7a+2,89= (0,5a+1,7)²
3)
8xy-88y²=8y(x-11y)