Home › UP Board Class 10 › mathematics › Introduction to Trigonometry › The identity $1 + \tan^2\theta$ equals:
The identity $1 + \tan^2\theta$ equals:
A$\cot^2\theta$
B$\csc^2\theta$
C$\sec^2\theta$
D$\cos^2\theta$
Answer & Solution
Correct answer: C. $\sec^2\theta$
Dividing sin²+cos²=1 by cos²θ gives 1 + tan²θ = sec²θ.