acosB=（3c-b)cosA
sinAcosB=3sinCcosA-sinBcosA
sinAcosB+sinBcosA=3sinC
sin(A+B)=3sinCcosA
sinC=3sinCcosA
cosA=1/3
sinA=√[1-(cosA)^2]=2√2/3
a/sinA=b/sinB
bsinA=asinB
b=asinB/sinA==2√2/(2√2/3)=3
b=3
2)S=1/2bcsinA=√2
1/2bc*2√2/3=√2
bc=3
b^2+c^2-2bc*(1/3)=(2√2)^2
(b+c)^2-(8/3)bc=8
(b+c)^2=8+(8/3)bc
(b+c)^2=8+(8/3)*3
(b+c)^2=16
b+c=4
a+b+c=4+2√2
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