Exercise $2(13$ points$)$

Solve the differential equation by variation of parameters

$y^{\text{'}\text{'}}y=secx$

Possible Answers

$($a$.)y=C_{1}cosx{C}_{2}sinxxcosxtanx$

$($b$.)y=C_{1}cosx{C}_{2}sinxxsinxsinxln|cosx|$

$($c$.)y=C_{1}cosx{C}_{2}sinxsecx$

$($d$.)y=C_{1}cosx{C}_{2}sinxxsinxcosxln|cosx|$

$($e$.)$ None of the above

Show your work.