角A+角B≤60°,证明sinA+sinB≤1

问题描述:

角A+角B≤60°,证明sinA+sinB≤1

证明:∵∠A+∠B=60º∴∠B=60º-∠AsinA+sinB=sinA+sin(60º-A)=sinA+sin60ºcosA-cos60ºsinA=sinA+√3/2*cosA-1/2*sinA=√3/2*cosA+1/2*sinA=sin60ºcosA+cos60ºsinA=sin(60º+...