Step-by-step explanation:
[tex](\sec A - \csc A)(1 + \cot A + \tan A)[/tex]
[tex]=(\sec A - \csc A)\left(1 + \dfrac{\cos A}{\sin A} + \dfrac{\sin A}{\cos A} \right)[/tex]
[tex]=(\sec A - \csc A)\left(1 + \dfrac{\cos^2 A + \sin^2 A}{\sin A\cos A} \right)[/tex]
[tex]=(\sec A - \csc A)\left(\dfrac{1 + \sin A \cos A}{\sin A \cos A} \right)[/tex]
[tex]=\left(\dfrac{\frac{1}{\cos A} - \frac{1}{\sin A}+\sin A - \cos A}{\sin A\cos A}\right)[/tex]
[tex]=\dfrac{\sin A - \sin A \cos^2A - \cos A + \cos A\sin^2A}{(\sin A\cos A)^2}[/tex]
[tex]=\dfrac{\sin A(1 - \cos^2A) - \cos A (1 - \sin^2 A)}{(\sin A\cos A)^2}[/tex]
[tex]=\dfrac{\sin^3A - \cos^3A}{\sin^2A\cos^2A}[/tex]
[tex]=\dfrac{\sin A}{\cos^2A} - \dfrac{\cos A}{\sin^2A}[/tex]
[tex]=\left(\dfrac{1}{\cos A}\right)\left(\dfrac{\sin A}{1}\right) - \left(\dfrac{1}{\sin^2A}\right) \left(\dfrac{\cos A}{1}\right)[/tex]
[tex]=\sec^2A\csc A - \csc^2A\sec A[/tex]
