It is not true to write so: 2/cos^2x + 3sinx/cos^2x nor 2/cosx+3sinx/cos x

We can write it so:

a) [ 2(cosx)^2 + 3sinx] /(cosx)^2

b) We can substitute sinx/cosx = tanx and 1/cosx = secx ... then it is

2 + 3tanx * secx OK!

Question has no meaning.

What is meant by "decompose?"

Why are there no brackets?

Can but GUESS at :-

(2 + 3 sin x) / cos²x

2/cos²x + 3 sin x / cos²x

2 sec²x + 3 tan x sec x