The identity $1 + \tan^2\theta$ equals:
A$1$
B$\sec^2\theta$
C$\cot^2\theta$
D$\csc^2\theta$
Answer & Solution
Correct answer: B. $\sec^2\theta$
Dividing sin²θ+cos²θ=1 by cos²θ gives tan²θ+1 = sec²θ.
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