Given that, sinx-cosx-tanx=-1.
:. sinx-cosx-sinx/cosx+1=0.
:. (sinx-cosx)-(sinx/cosx-1)=0.
:. (sinx-cosx)-(sinx-cosx)/cosx=0.
:. (sinx-cosx)cosx-(sinx-cosx)=0.
:. (sinx-cosx)(cosx-1)=0.
:. sinx=cosx or cosx=1.
" Case 1 : "sinx=cosx.
Observe that cosx!=0, because," if otherwise; "tanx" becomes"
undefined.
Hence, dividing by cosx!=0, sinx/cosx=1, or, tanx=1.
:. tanx=tan(pi/4).
:. x=kpi+pi/4, k in ZZ," in this case".
" Case 2 : "cosx=1.
"In this case, "cosx=1=cos0, :. x=2kpi+-0, k in ZZ.
Altogether, we have,
"The Solution Set"={2kpi}uu{kpi+pi/4}, k in ZZ.