$\dfrac{1 - an^2 A}{1 - \cot^2 A}$ equals to:

Question

$\dfrac{1 - 	an^2 A}{1 - \cot^2 A}$ equals to:

Accepted Answer

## Model Answer **(C) $-	an^2 A$** $$\frac{1-	an^2 A}{1-\cot^2 A} = \frac{1-	an^2 A}{1-\dfrac{1}{	an^2 A}} = \frac{1-	an^2 A}{\dfrac{	an^2 A -1}{	an^2 A}} = \frac{(1-	an^2 A)\cdot	an^2 A}{-(1-	an^2 A)} = -	an^2 A$$ ## Explanation Examiners expect you to show the simplification step (replace $\cot^2 A = \frac{1}{	an^2 A}$), then cancel the common factor $(1-	an^2 A)$. Note this is different from Exercise 8.3 Q3(iv) which has *plus* signs; here the minus signs flip the denominator's sign, giving the negative answer. Always justify MCQ choices with at least one working step.

Mathematics — Standard (041) — CBSE Class 10 board question