There's a guy on youtube.com explaining what he calls RATIONAL TRIGONOMETRY.
What level of math is that?
What is the use of such trigonometry?
what did the guy say when he was talking about Rational Trigonometry?
The level varies, it can go from low level high school geometry, to higher levels. it is formulated a bit differently from regular trig though. so it might not be an approach taught widely in high school.
the use of such trig is the same as regular trig. only applied differently, with different notation and perhaps in different contexts. see Rational trigonometry - Wikipedia, the free encyclopedia
(I know it's a late reply, but someone reported this post and i wanted to answer it)
Here's what the guy looks like and what is teaching:
YouTube - WildTrig4: Five main laws of rational trigonometry
well, as you may be able to tell, this is just a reformulation of good ol' fashioned trigonometry. if you pay close attention, you will notice that these "laws" he is referring to, are things like Pythaogoras' theorem, the law of sines, the law of cosines, etc. he just calls them by different names and use different elements in the formula. for instance, see what happens if you replace "spread of two lines" with "the sine of the angle between the two lines", you will notice that spread is talking about the old sine = opposite/hypotenuse ratio. so it is really familiar trig in a new light. as for the advantages of this new formulation, i am not aware of what they are, but i am sure there are some, or else no one would waste time coming up with it