• Kecessa@sh.itjust.works
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        2 months ago

        I haven’t had to do anything with sin, cos or tan in over 20 years and even back then it’s a miracle I managed to pass my advanced math course considering I never understood what they were because it was so badly explained to us…

            • Feathercrown@lemmy.world
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              2 months ago

              sin(x) and cos(x) return the side lengths of a triangle with hypotenuse 1 and angle x, like so:

              I also was never taught this, which sucks because it’s such a useful concept.

              You can verify that if the angle (x) was 0, cos(x) would be 1, and sin(x) would be 0. If the angle was 90 degrees (vertical), then cos(x) would be 0 and sin(x) would be 1. If the angle was 45 degrees, cos(x) and sin(x) would have the same value, because the triangle sides would have the same length.

              • BearOfaTime@lemm.ee
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                2 months ago

                But why?

                See, I was taught this, but no one could every answer why sine and cosine worked the way they did.

                This definition just explains how they work with triangles. What’s the actual definition of each, and how was that derived? I can apply them all day long yet I still can’t tell you what either one means.

                I had the same issues with different kinds of equations, no one ever explained why you’d do a certain thing in a given step (e.g. Quadratic) even when I asked, repeatedly. The answer was always “you just do”. Well that doesn’t help with knowing when to apply a rule.

                And that was my experience with any math, right through college (3 universities). Most teachers suck, but holy shit math teachers are down right moronic. They can’t understand why students don’t get it. Well, try actually teaching something for a fucking change.

    • radicalautonomy@lemmy.world
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      2 months ago

      It’s called a literal equation. The problem doesn’t state which variable to solve for, but the assumption here is that it is x. Solving literal equations is a basic part of mathematics courses.

      • Leate_Wonceslace@lemmy.dbzer0.com
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        2 months ago

        I’m a mathematician and I can’t recall a time I’ve ever heard the term “literal equation.” When I was in grade school the instructions were always “solve for x” if x was the variable being solved for.

        • radicalautonomy@lemmy.world
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          2 months ago

          I teach secondary and postsecondary math courses. The term “literal equation” was used in Texas where I taught for 17 years. The Algebra 1 state standard A.12E says that students are expected to “solve mathematic and scientific formulas, and other literal equations, for a specified variable.” I also taught college undergrad courses in Texas, including College Algebra, and I don’t recall ever seeing the the term used there, but I used it in class because my students were familiar with it. Now I teach in Oregon, and the term is not a part of this state’s standards from what I can tell.

        • Funkytom467@lemmy.world
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          2 months ago

          Maybe it’s not universal but in school literal equation basically meant there were letters instead of numbers.

          It’s the term we use for instance when going from the equation of a line like y=3x+2 to lines in general y=ax+b (a and b in ℝ)

          And i agree it’s a lot better to specify to solve for x (because you can solve for anything or have multiple variables).

          Although x being a variable, and solving for it would be the most logical assumption.

  • sag@lemm.ee
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    2 months ago

    WTF bro, There is 3 variables.

    Wait? NVM Wait?

    Today I did Calculus for 6 hour straight. So, don’t mind me I am just tired.

  • lustyargonian@lemm.ee
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    2 months ago

    x = arcsin (kn - 1)

    I’ve solved it. There you go. I hope you use this solution for something good.

      • schema@lemmy.world
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        2 months ago

        Considering the handwriting, it’s probably all written by the same person. But even if it wasn’t, it is very badly written if you had to solve it by making assumptions, imo.