Prove the following trigonometric identities sec thetatan th
     Prove the following trigonometric identities.  sec theta/tan theta = csc theta  (sec x + tan x)(1 - sin x/cos x) = 1   
  
  Solution
sec theta/tan theta=csc theta
sec theta=1/cos theta (reciprocal rule)
and tan theta=sin theta/cos theta (quotient rule)
1/cos theta/sin theta/cos theta (substitution postulate)
1/sin theta = csc theta (reciprocal rule)

