Final answer:
In aviation, 'MAG' refers to magnetic heading, while 'TRU' refers to true heading, both of which can appear on a Primary Flight Display's Attitude Direction Indicator.
Step-by-step explanation:
In the context provided, 'MAG' typically refers to magnetic heading, which is the aircraft's direction relative to the Earth's magnetic North. 'TRU' stands for True heading, which is the aircraft's direction relative to the Earth's true North. These terms are regularly used in aviation, specifically when discussing navigational readings on a Primary Flight Display (PFD). On a PFD, the Attitude Direction Indicator (ADI) may show both types of headings. The reference to trigonometry and the notation 'Fnet x TLX' suggests that this question may include a calculation using trigonometric relationships to solve for the magnitude of vectors, possibly relating to forces acting on the aircraft.