1.=[(a+b+c)-2(a^2+b^2+c^2)+(a^3+b^3+c^3)]/abc
Because A+B+C = 2 = A2+B2+C2-> AB+BC+AC =1
-& gt； a^3+b^3+c^3=(a+b+c)(a^2+b^2+c^2)-(a+b+c)(ab+bc+ac)+3abc=2+3abc
Original formula =[2-4+2+3abc]/abc=3.
4。 This ratio is a, a 2+a > 1, a < 1, so c is chosen.
5.a= 10
Tana = A. I don't know what other conditions mean. . .
8. In fact, the three sides of a triangle are X, Y, z Y and Z. Find the sum of the distances from Fermat to the three sides. The conclusion is the root number 199.