Does this mean that trigonometry also accounts for 50% headwind and 150% tailwind?
Definitely not.
The graph 4.1 gives the same HW & TW component when the wind is 50 degs off the runway and 130 degs off. i.e. 19 Kts Head Wind and 19 Kts Tail Wind - so they are not factored on that graph.
The performance chart 4.4 has different scales for Head & Tail wind and the reference line is slightly biased to give a bigger penalty for a tail wind. I think that is what they refer to when they say "the chart has already accounted for 50% headwind and 150% tailwind" - but please check with your instructor.