Question

- if sec2 θ + tan2 θ = 5/3, then what is the value of tan 2θ?

Answer 1

WKT (sec2x)^2-(tan2x)^2=1
LHS =
(sec2x+tan2x)(sec2x-tan2x)
this implies that sec2x-tan2x=3/5. ---(1)
we also know that sec2x+tan2x =5/3----(2)
subtract (2) from (1). and get the value of tan2x.