Simplify: sinx−sinycosx+cosy+cosx−cosysinx+ siny
Answer:
0
- sinx−sinycosx+cosy+cosx−cosysinx+ siny=(sinx−siny)(sinx+siny)+(cosx+cosy)(cosx−cosy)(cosx+cosy)(sinx+ siny)=sin2x−sin2y+cos2x−cos2y(cosx+cosy)(sinx+ siny)=1−1(cosx+cosy)(sinx+ siny) [sin2θ+cos2θ=1]=0