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Math Help - Calculating the value for cotangent.

  1. #1
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    Calculating the value for cotangent.

    My question says to "calculate the value for cotangent (0) if (0)=270 degrees, given in standard position"

    Just calculating it and getting 1.8370 I got it counted wrong, and when I asked on another forum about it they had gone through and what seems like to me, they used quotient identities and put the cos(270)/(sin(270) to equal 0.

    Is that the right way to go about this? It didn't say to use quotient identities so I wasn't sure.

    There's a second question with the same degree but its asking for the csc (cosecant) of 270, given in standard position.
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  2. #2
    MHF Contributor Also sprach Zarathustra's Avatar
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    Re: Calculating the value for cotangent.

    Quote Originally Posted by sterces View Post
    My question says to "calculate the value for cotangent (0) if (0)=270 degrees, given in standard position"

    Just calculating it and getting 1.8370 I got it counted wrong, and when I asked on another forum about it they had gone through and what seems like to me, they used quotient identities and put the cos(270)/(sin(270) to equal 0.

    Is that the right way to go about this? It didn't say to use quotient identities so I wasn't sure.

    There's a second question with the same degree but its asking for the csc (cosecant) of 270, given in standard position.
    ...some smart people you found out there...

    It's true.
    \theta=270^{\circ}
    \cot(\theta)=\frac{\cos(\theta)}{\sin(\theta)}=\fr  ac{\cos(270^{\circ})}{\sin(270^{\circ})}=\frac{0}{-1}=0

    EDIT:
    \sec(\theta)=\frac{1}{\cos(\theta)}

    So, what is \sec(270^{\circ}) ?
    Last edited by Also sprach Zarathustra; June 30th 2011 at 08:35 AM.
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  3. #3
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    Re: Calculating the value for cotangent.

    Ah, alright, thanks for verifying
    sec(270) would be -1 then.
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    MHF Contributor Also sprach Zarathustra's Avatar
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    Re: Calculating the value for cotangent.

    Quote Originally Posted by sterces View Post
    Ah, alright, thanks for verifying
    sec(270) would be -1 then.
    Yes!(But only by my definition of sec function)
    Last edited by Also sprach Zarathustra; June 30th 2011 at 08:32 AM.
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  5. #5
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    Re: Calculating the value for cotangent.

    Quote Originally Posted by Also sprach Zarathustra View Post

    \sec(\theta)=\frac{1}{\sin(\theta)}
    \sec(x) = \dfrac{1}{\cos(x)} rather than 1/sin(x).
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  6. #6
    MHF Contributor Also sprach Zarathustra's Avatar
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    Re: Calculating the value for cotangent.

    Quote Originally Posted by sterces View Post
    Ah, alright, thanks for verifying
    sec(270) would be -1 then.

    No!

    sec(270)=1/cos(270)=1/0
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  7. #7
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    Re: Calculating the value for cotangent.

    Quote Originally Posted by Also sprach Zarathustra View Post
    No!

    sec(270)=1/cos(270)=1/0
    But the question doesn't ask for \sec(270^\circ), it asks for \csc(270^\circ) = \frac1{\sin(270^\circ)} = \frac1{-1} = -1.
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