直接等式两边约分就完了.
∵S=1/2absinC,S=1/2bcsinA, S=1/2acsinB,
∴1/2absinC=1/2bcsinA,1/2acsinB=1/2bcsinA,1/2acsinB=1/2absinC
asinC=csinA,asinB=bsinA,csinB=bsinC
a/sinA=c/sinC,a/sinA=b/sinB,c/sinC=b/sinB
∴a/sinA=b/sinB=c/sinC
直接等式两边约分就完了.
∵S=1/2absinC,S=1/2bcsinA, S=1/2acsinB,
∴1/2absinC=1/2bcsinA,1/2acsinB=1/2bcsinA,1/2acsinB=1/2absinC
asinC=csinA,asinB=bsinA,csinB=bsinC
a/sinA=c/sinC,a/sinA=b/sinB,c/sinC=b/sinB
∴a/sinA=b/sinB=c/sinC