Expression : $$\dfrac{(1 + cosA)}{(1 - cosA)}$$ = x
Multiplying both numerator and denominator by $$(1-cosA)$$
= $$\dfrac{1+cosA}{1-cosA} \times \dfrac{(1-cosA)}{(1-cosA)}$$
= $$\dfrac{1-cos^2A}{(1-cosA)^2} = \dfrac{sin^2A}{(1-cosA)^2}$$
Dividing both numerator and denominator by $$(cos^2A)$$
= $$\dfrac{sin^2A}{cos^2A}\div\dfrac{(1-cosA)^2}{cos^2A}$$
= $$tan^2A \div (\dfrac{1-cosA}{cosA})^2$$
= $$\dfrac{tan^2A}{(secA-1)^2}$$
=> Ans - (D)
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