Which of the following identities is always true for every admissible value of ?

MATHEMATICS · Single correct · CBSE · Mathematics · Introduction to Trigonometry · Introduction to Trigonometry

Problem

Which of the following identities is always true for every admissible value of

\theta

? (a)

\tan^{2}\theta+1=\csc^{2}\theta

(b)

\sin^{2}\theta+\cos^{2}\theta=\sec\theta

(c)

\cos\theta\,\sec\theta=1

(d)

1+\cot^{2}\theta=\sec^{2}\theta