Question

若A,B为实数,且A2+4B2-2A+4B+2=0,要4A2+B分之一的值

Answer 1

(A^2-2A+1)+(4B^2+4B+1)=(A-1)^2+(2B+1)^2=0因A,B是实数,(A-1)^2>=0,(2B+1)^2>=0

则(A-1)^2=0,(2B+1)^2=0A=1,B=-1/2

1/(4A^2+B)=2/7