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highschoolmom2010

  • one year ago

trigonometric functions

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  1. highschoolmom2010
    • one year ago
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  2. agent0smith
    • one year ago
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    Well, you can start by testing a couple of values, to disprove it immediately try A=30 and B=59 Tan30 + tan59 = tan89 ?

  3. terenzreignz
    • one year ago
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    I for one, do not recall the tangent identity to be quite as simple as tan(A) + tan(B) = tan(A + B)...

  4. agent0smith
    • one year ago
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    It's not @terenzreignz, but the question states for A+B< 90 which makes it not able to be an identity. But it's easy to disprove.

  5. terenzreignz
    • one year ago
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    Why not tan(45) + tan(30) = tan(75) :)

  6. pgpilot326
    • one year ago
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    tan 45 = 1. tan 22.5 <> .5

  7. agent0smith
    • one year ago
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    ^that also disproves it, @highschoolmom2010

  8. katherine.ok
    • one year ago
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    basically tana+tanb= (sinacosb+sinbcosa)/cosacosb= sin(a+b)/cosacosb

  9. terenzreignz
    • one year ago
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    At least we have exact values for these stuff :3 \[\Large \tan(45^o) = 1\\\Large \tan(30^o)=\frac1{\sqrt{3}}\]

  10. agent0smith
    • one year ago
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    My reasoning for picking a A+B close to 90, was due to tan90 being undefined, so it's highly unlikely two smaller angles will give anything close to the tangent of an angle near 90

  11. katherine.ok
    • one year ago
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    =(sinacosb+cosasinb)/cosacosb=/= sinasinb/cosacosb

  12. terenzreignz
    • one year ago
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    Noted :)

  13. katherine.ok
    • one year ago
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    Now i need to somehow prove sinacosb+sinbcosa=/=sinasinb...

  14. agent0smith
    • one year ago
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    @katherine.ok based on her other questions, I don't think she's at the level of trigonometry where they're using proofs. I think it's more an analytical question.

  15. pgpilot326
    • one year ago
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    tan 60 + tan (-30) <> tan 30

  16. katherine.ok
    • one year ago
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    I think as simple as this sound...

  17. katherine.ok
    • one year ago
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    by using the tangent graph, adding a random point where x is (0,90),you will not get tan a+ tan b because it is not linear graph.

  18. agent0smith
    • one year ago
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    ^ good point.

  19. highschoolmom2010
    • one year ago
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    im lost on all of this tbh....

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