Question

已知直线l1:x+a^2y+1=0和直线l2:(a^2+1)x-by+3=o (a,b)∈R

Answer 1

a^2>=01/(a^2+1)=a^2/(-b) -b=a^4+a^2=a^4+a^2+1/4-1/4=(a^2+1/2)^2-1/4>=1/4-1/4=0