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Math problem help

  1. Mar 13, 2004 #1
    math problem help!!

    hello everybody, how's it going? well, i had a problem with this math homework that i am tearing my hair out about it!!

    here is my problem:

    the directions for this problem says this:

    Find each value. Express theta (i don't know how to make that greek letter of theta on here, it is a cirlce with a

    line in the middle of it i hope you get what i mean )
    in radians to the nearest hundredth.
    5. Arctan of the square root of 6 (I don't know how to make the arctan and the square root symbols on here sorry

    for writing it all out ).


    this is what i did, i just took my TI-83 (it's not a TI-83 Plus, just a regular one) and i just put it in there. i got this answer,

    approximately 67.79

    i thought that i was done, but when i looked in the back of the book to see if i got number five (this problem) right, i

    didn't get it right!! they had this answer in the back: 1.18

    how on earth did they get that??

    can someone please help me? thank you very much for helping me!!
     
  2. jcsd
  3. Mar 13, 2004 #2
    Your calculator is giving you your answers in degrees. You need to convert 67 degrees to radians. Do you remember how many degrees are in a radian?

    cookiemonster
     
  4. Mar 13, 2004 #3
    wut do you mean? not i don't remember sorry bro.:frown: :frown:

    btw is it 30 degrees in a radian?[?]
     
    Last edited: Mar 13, 2004
  5. Mar 13, 2004 #4

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    1. Homework should be posted the "homework zone" (I'm "mentor" for the homework zone so I'm kinda hardnosed about that. It's a jurisdictional thing!).

    2. Put your calculator in "radian" mode!!! There is a button on your TI-83 that says "mode". Press that and you find a menu including one for angles that probably says "degrees" now. move down to that and select "radians".
    No, there are not "30 degrees in a radian". Radian measure is based on the circumference of the unit circle. There are 2π radians in a full circle so π/2 radians in 90 degrees, therefore, π/6 radians in 30 degrees. That's just a little bit more than 1/2 radian in 30 degrees. If your teacher is expecting you to do problems like this you really had better go back and review the definition of "radian". For this problem you don't really need to do that: just use "radian mode" on your calculator. Of course, then you get the answer without really understanding it!

    3. You can make a θ by typing "& theta ;" without the spaces (and without the "!). I wouldn't use a special arctan symbol. for arctan(sqrt(6)) (which is a perfectly valid way of writing it) I would use "arctan(√(6))" and I got the √ by typing "& radic ;"-again without the spaces. If you really want to use tan-1(√(6)) just type "tan[ sup /]-1[ /sup ](& radic ;(6)) without the spaces.
    If you want to be really fancy you can use "tex":
    [tex]\theta= tan^{-1}(\sqrt{6}) [/tex].

    Just click on that to see the "code".
     
    Last edited: Mar 13, 2004
  6. Mar 13, 2004 #5
    bro thank you sooooo much!! you don't now wut this means to me!!

    i'm really really sorry about the misplacement of this thread!:frown: thank you for your patience and the help!

    i was in a hurry and so this is why i put it in the "general math" section. if its possible, can you move it to the right section?

    THANK YOU AGAIN!!
     
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