Note that...
sin2(w)+cos2(w)=1→sin2(w)sin2(w)+cos2(w)sin2(w)=1sin2(w)→1+cot2(w)=csc2(w)
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csc3(w)=cot3(w)+cot(w)cos(w) =cot(w)(cot2(w)+1)cos(w) =cot(w)(1+cot2(w))cos(w) =cot(w)csc2(w)cos(w) =1cos(w)⋅cot(w)⋅csc2(w) =1cos(w)⋅cos(w)sin(w)⋅csc2(w) =1sin(w)⋅csc2(w) =csc(w)⋅csc2(w) =csc3(w)
Verify (Prove) Each Identity
csc^3(w)=\frac{cot^3(w)+cot(w)}{cos(w)}
csc3(w)=cot3(w)+cot(w)cos(w)
csc3(w)=cot3(w)+cot(w)cos(w)=cot(w)⋅(cot2(w)+1)cos(w)|cot(w)=cos(w)sin(w)=cos(w)sin(w)⋅(cos2(w)sin2(w)+1)cos(w)=cos(w)sin(w)⋅(cos2(w)+sin2(w)sin2(w))cos(w)|cot2(w)+sin2(w)=1=cos(w)sin(w)⋅(1sin2(w))cos(w)=cos(w)sin3(w)cos(w)=cos(w)sin3(w)cos(w)=1sin3(w)|1sin(w)=csc(w)=csc3(w)