Question

solve this question by using trigonometric identities.

Answer 1

here is the another way to calculate the value of sec@
as we know.

sec^2@- tan^2@=1
(sec@+tan@) (sec@-tan@)=1............(1)

using a^2 - b^2=(a+b)(a-b)
sec@+tan@ =x

using eqn (1)

sec@ - tan@ =1/x...........(2)

add eqn 1 & eqn 2

2sec@=(x + 1/x)
:• sec@ = [1/2] (x+ 1/x)