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A-level trig, CAST vs sketch graph Watch

  • View Poll Results: cast vs graph
    CAST
    6
    60.00%
    sketch graph of sin,cos,tan
    4
    40.00%

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    So just wondering which method people use to find multiple solutions for trig functions. Personally I always use the graph and the symmetry from the graphs to find multiple solutions and it works if I'm on the ball. I've never understood cast but I understand that a lot of people are taught that way.
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    (Original post by black1blade)
    So just wondering which method people use to find multiple solutions for trig functions. Personally I always use the graph and the symmetry from the graphs to find multiple solutions and it works if I'm on the ball. I've never understood cast but I understand that a lot of people are taught that way.
    Sketch the graphs. Always works.I don't even know why people use CAST; sketching the graphs are just better. You need to know the graphs for A2 anyway.
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    I do both, it doesn't hurt. I usually use CAST first though since it's quick to get the values. In the end, it's down to how comfortable you are with it.
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    (Original post by boriapple)
    I do both, it doesn't hurt. I usually use CAST first though since it's quick to get the values. In the end, it's down to how comfortable you are with it.
    Guess thing is that cast is a bit more geometric and I don't find geometry very intuitive. I would rather just see multiple solutions when y=1/2 or whatever rather than have to think about loads of triangle and stuff (which is where cast comes from right?). Maybe I wouldn't be a great maths teacher- we aren't learning this method- it's dumb! Also I might make another poll but I still do y=mx+c when finding tangents and normals.
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    Sometimes I imagine a cast diagram, sometimes I just do it from memory.
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    (Original post by black1blade)
    So just wondering which method people use to find multiple solutions for trig functions. Personally I always use the graph and the symmetry from the graphs to find multiple solutions and it works if I'm on the ball. I've never understood cast but I understand that a lot of people are taught that way.
    General solutions
 
 
 
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