第1个回答 2013-10-14
余弦定理b/sinB=c/sinC,∴csinB=bsinC,∴a=bcosC+csinB=bcosC+bsinC=b(cosC+sinC)=b√2sin(C+π/4)=2√2sin(C+π/4). S⊿ABC=1/2absinC=2√2sin(C+π/4)sinC=2sin�0�5C+2sinCcosC=sin2C-cos2C+1=√2sin(2C-π/4)+1. 当C=3π/8时,S⊿ABC取最大值,S⊿ABCmax=√2+1. sinB=bsinC/c,B=arcsin(bsinC/c).本回答被网友采纳