Respuesta :

Solution:

[tex]\dfrac{\left[\left(\sin ^{2} A+2 \times \sin A \times (1-\cos A)+(1-\cos A)^{2}\right]\right.}{\left[\left(1-\cos ^{2} A\right)-(1-\cos A)^{2}\right]}[/tex]

[tex]\dfrac{\left[\left(1-\cos ^{2} A\right)+2 \times \sin A \times (1-\cos A)+(1-\cos A)^{2}\right]}{\left[(1-\cos A)(1+\cos A)-(1-\cos A)^{2}\right]} [/tex]

[tex]\dfrac{(1-\cos A)[1+\cos A+2 \sin A+1-\cos A]}{[1-\cos A][1+\cos A-1+\cos A]} [/tex]

[tex]\dfrac{[2+2 \sin A]}{[2 \times \cos A]}[/tex]

[tex]\dfrac{2(1+\sin A)}{2 \times \cos A}[/tex]

[tex]\dfrac{1+\cos A}{\sin A} [/tex]

Hence Proved.

RELAXING NOICE
Relax