Question

请问这个正弦定理的变形公式是怎样得到的?

Answer 1

a/sinA=b/sinB=c/sinC=k

=>a=ksinA,b=ksinB,c=ksinC

=>a+b+c=ksinA+ksinB+ksinC=k(sinA+sinB+sinC)

=>(a+b+c)/(sinA+sinB+sinC)

=k(sinA+sinB+sinC)/(sinA+sinB+sinC)

=k

=a/sinA

=b/sinB

=c/sinC