The value of 1 / (1 + tan²θ) is equivalent to:

Correct option is D

Given:
Expression to evaluate:
1 / (1 + tan²θ)
​
Formula Used:
1 + tan²θ = sec²θ
1 / sec²θ = cos²θ

Solution:
Start with the expression:
1 / (1 + tan²θ)

Using the identity:
1 + tan²θ = sec²θ
So,
​$$\frac{1}{1 + \tan^2 \theta} = \frac{1}{\sec^2 \theta} = \cos^2 \theta$$​​

Final Answer: (D) cos²θ