Q.The minimum value of \( \cos^2\theta + \sec^2\theta \) is: (a) -2 (b) 1 (c) 2 (d) -1
Answer: C
\[ \cos^2\theta + \sec^2\theta \] \[ = (\cos\theta - \sec\theta)^2 + 2\cos\theta \cdot \sec\theta \] \[ = (\cos\theta - \sec\theta)^2 + 2\cos\theta \cdot \frac{1}{\cos\theta} \] \[ = (\cos\theta - \sec\theta)^2 + 2 \] \[ > 2 \]
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