Respuesta :

LammettHash
[tex]\dfrac{\cot x}{\csc x-\sin x}=\dfrac{\cot x\sin x}{(\csc x-\sin x)\sin x}=\dfrac{\cos x}{1-\sin^2x}=\dfrac{\cos x}{\cos^2x}=\dfrac1{\cos x}=\sec x[/tex]