Question 85

What is the value of $$\sqrt{[\frac{(1 - cosA)}{(1 + cosA)}]}$$ ?

Solution

Expression : $$\sqrt{[\frac{(1 - cosA)}{(1 + cosA)}}]$$

Multiplying both numerator and denominator by $$(\sqrt{1+cosA})$$

= $$\sqrt{[\frac{(1 - cosA)}{(1 + cosA)}}]$$ $$\times \sqrt{\frac{(1+cosA)}{(1+cosA)}}$$

= $$\sqrt{\frac{1-cos^2A}{(1+cosA)^2}} = \sqrt{\frac{sin^2A}{(1+cosA)^2}}$$

= $$\frac{sinA}{1+cosA}$$

=> Ans - (B)

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