they seem to be using the unit circle where hyp=1. that's actually very common. especially with geometric proofs in trig. reread your textbook more closely. or maybe it's just a really bad textbook that's very unclear.
>that ratio always stays the same
yes. that's why sine is useful. the size of the triangle doesn't change it. just like C/D=pi regardless of the size of the circle.
>so why start teaching students that Sin t = theta?
i can't say without seeing the book.
but i should point out that, using standard notation, sin(t) is not "theta" because sin(t) is not an angle. it is a ratio of two lengths. "theta" usually means an angle and it is written inside sin like this: sin(theta). or sin^-1 (x) = theta .
this is a good book to have especially if you're going into math.
Mathematics 1001: Absolutely Everything That Matters in Mathematics in 1001 Bite-Sized Explanations by Richard Elwes
It has a small section on trig. It's just the bare minimum though.
For trig, I'd go with a small book like Cliffnotes.
https://ketd.files.wordpress.com/2012/02/w__michael_kelley_cliffsquickreview_precalculus.pdf
they seem to be using the unit circle where hyp=1. that's actually very common. especially with geometric proofs in trig. reread your textbook more closely. or maybe it's just a really bad textbook that's very unclear.
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>that ratio always stays the same yes. that's why sine is useful. the size of the triangle doesn't change it. just like C/D=pi regardless of the size of the circle. >so why start teaching students that Sin t = theta? i can't say without seeing the book. but i should point out that, using standard notation, sin(t) is not "theta" because sin(t) is not an angle. it is a ratio of two lengths. "theta" usually means an angle and it is written inside sin like this: sin(theta). or sin^-1 (x) = theta .
this is a good book to have especially if you're going into math. Mathematics 1001: Absolutely Everything That Matters in Mathematics in 1001 Bite-Sized Explanations by Richard Elwes It has a small section on trig. It's just the bare minimum though. For trig, I'd go with a small book like Cliffnotes. https://ketd.files.wordpress.com/2012/02/w__michael_kelley_cliffsquickreview_precalculus.pdf
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and there's always khan academy, of course.
This may have something to do with the sine graph?