If sinx+cosx=a, then |sinx−cosx| equals
If sinx+siny=a and cosx+cosy=b show that tan(x−y2)=±√(4−a2−b2a2+b2)
If sinx+siny=a and cosx+cosy=b show that cos(x−y)=(a2+b2−2)/2
If (sinx+cosx=a), then 1+2sinxcosx=a2