$A.\ sen\theta$

$B.\ \cos\theta$

$C.\ \cot\theta$

$D.\ \sec\theta$

$E.\ \csc\theta$

A. sec x - csc x

B. sec x

C. csc x

D. sec x + csc x

E. tan x + cot x

$A.\ sen^{4\ }x$

$B.\ \sec\ x$

$C.\ \csc\ x$

$D.\ \sec\ x\ +\ \csc\ x$

$E.\ \tan\ x\ +\ \cot\ x$

$A.sen\theta$

$B.\ \cos\theta$

$C.\ \tan\theta$

$D.\ \cot\theta$

$E.\ 1$